diff --git a/Changelog.md b/Changelog.md
new file mode 100644
--- /dev/null
+++ b/Changelog.md
@@ -0,0 +1,5 @@
+# Changelog
+
+## 0.1.0
+
+- Initial release
diff --git a/LICENSE b/LICENSE
new file mode 100644
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,95 @@
+Copyright (c) 2017, Composewell Technologies
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+this list of conditions and the following disclaimer in the documentation
+and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its contributors
+may be used to endorse or promote products derived from this software without
+specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+-------------------------------------------------------------------------------
+fsnotify-0.3.0.1 (http://hackage.haskell.org/package/fsnotify-0.3.0.1/)
+-------------------------------------------------------------------------------
+Copyright (c) 2012, Mark Dittmer
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Mark Dittmer nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+-------------------------------------------------------------------------------
+hfsevents-0.1.6 (http://hackage.haskell.org/package/hfsevents-0.1.6)
+-------------------------------------------------------------------------------
+Copyright (c) 2012, Luite Stegeman
+
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above
+      copyright notice, this list of conditions and the following
+      disclaimer in the documentation and/or other materials provided
+      with the distribution.
+
+    * Neither the name of Luite Stegeman nor the names of other
+      contributors may be used to endorse or promote products derived
+      from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/README.md b/README.md
new file mode 100644
--- /dev/null
+++ b/README.md
@@ -0,0 +1,2 @@
+Please refer to the [streamly](https://github.com/composewell/streamly/blob/master/docs/User/Project/README.md)
+package for tutorials and other documentation.
diff --git a/Setup.hs b/Setup.hs
new file mode 100644
--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,6 @@
+module Main (main) where
+
+import Distribution.Simple
+
+main :: IO ()
+main = defaultMainWithHooks autoconfUserHooks
diff --git a/configure b/configure
new file mode 100644
--- /dev/null
+++ b/configure
@@ -0,0 +1,4317 @@
+#! /bin/sh
+# Guess values for system-dependent variables and create Makefiles.
+# Generated by GNU Autoconf 2.71 for streamly 0.11.0.
+#
+# Report bugs to <streamly@composewell.com>.
+#
+#
+# Copyright (C) 1992-1996, 1998-2017, 2020-2021 Free Software Foundation,
+# Inc.
+#
+#
+# This configure script is free software; the Free Software Foundation
+# gives unlimited permission to copy, distribute and modify it.
+## -------------------- ##
+## M4sh Initialization. ##
+## -------------------- ##
+
+# Be more Bourne compatible
+DUALCASE=1; export DUALCASE # for MKS sh
+as_nop=:
+if test ${ZSH_VERSION+y} && (emulate sh) >/dev/null 2>&1
+then :
+  emulate sh
+  NULLCMD=:
+  # Pre-4.2 versions of Zsh do word splitting on ${1+"$@"}, which
+  # is contrary to our usage.  Disable this feature.
+  alias -g '${1+"$@"}'='"$@"'
+  setopt NO_GLOB_SUBST
+else $as_nop
+  case `(set -o) 2>/dev/null` in #(
+  *posix*) :
+    set -o posix ;; #(
+  *) :
+     ;;
+esac
+fi
+
+
+
+# Reset variables that may have inherited troublesome values from
+# the environment.
+
+# IFS needs to be set, to space, tab, and newline, in precisely that order.
+# (If _AS_PATH_WALK were called with IFS unset, it would have the
+# side effect of setting IFS to empty, thus disabling word splitting.)
+# Quoting is to prevent editors from complaining about space-tab.
+as_nl='
+'
+export as_nl
+IFS=" ""	$as_nl"
+
+PS1='$ '
+PS2='> '
+PS4='+ '
+
+# Ensure predictable behavior from utilities with locale-dependent output.
+LC_ALL=C
+export LC_ALL
+LANGUAGE=C
+export LANGUAGE
+
+# We cannot yet rely on "unset" to work, but we need these variables
+# to be unset--not just set to an empty or harmless value--now, to
+# avoid bugs in old shells (e.g. pre-3.0 UWIN ksh).  This construct
+# also avoids known problems related to "unset" and subshell syntax
+# in other old shells (e.g. bash 2.01 and pdksh 5.2.14).
+for as_var in BASH_ENV ENV MAIL MAILPATH CDPATH
+do eval test \${$as_var+y} \
+  && ( (unset $as_var) || exit 1) >/dev/null 2>&1 && unset $as_var || :
+done
+
+# Ensure that fds 0, 1, and 2 are open.
+if (exec 3>&0) 2>/dev/null; then :; else exec 0</dev/null; fi
+if (exec 3>&1) 2>/dev/null; then :; else exec 1>/dev/null; fi
+if (exec 3>&2)            ; then :; else exec 2>/dev/null; fi
+
+# The user is always right.
+if ${PATH_SEPARATOR+false} :; then
+  PATH_SEPARATOR=:
+  (PATH='/bin;/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 && {
+    (PATH='/bin:/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 ||
+      PATH_SEPARATOR=';'
+  }
+fi
+
+
+# Find who we are.  Look in the path if we contain no directory separator.
+as_myself=
+case $0 in #((
+  *[\\/]* ) as_myself=$0 ;;
+  *) as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    test -r "$as_dir$0" && as_myself=$as_dir$0 && break
+  done
+IFS=$as_save_IFS
+
+     ;;
+esac
+# We did not find ourselves, most probably we were run as `sh COMMAND'
+# in which case we are not to be found in the path.
+if test "x$as_myself" = x; then
+  as_myself=$0
+fi
+if test ! -f "$as_myself"; then
+  printf "%s\n" "$as_myself: error: cannot find myself; rerun with an absolute file name" >&2
+  exit 1
+fi
+
+
+# Use a proper internal environment variable to ensure we don't fall
+  # into an infinite loop, continuously re-executing ourselves.
+  if test x"${_as_can_reexec}" != xno && test "x$CONFIG_SHELL" != x; then
+    _as_can_reexec=no; export _as_can_reexec;
+    # We cannot yet assume a decent shell, so we have to provide a
+# neutralization value for shells without unset; and this also
+# works around shells that cannot unset nonexistent variables.
+# Preserve -v and -x to the replacement shell.
+BASH_ENV=/dev/null
+ENV=/dev/null
+(unset BASH_ENV) >/dev/null 2>&1 && unset BASH_ENV ENV
+case $- in # ((((
+  *v*x* | *x*v* ) as_opts=-vx ;;
+  *v* ) as_opts=-v ;;
+  *x* ) as_opts=-x ;;
+  * ) as_opts= ;;
+esac
+exec $CONFIG_SHELL $as_opts "$as_myself" ${1+"$@"}
+# Admittedly, this is quite paranoid, since all the known shells bail
+# out after a failed `exec'.
+printf "%s\n" "$0: could not re-execute with $CONFIG_SHELL" >&2
+exit 255
+  fi
+  # We don't want this to propagate to other subprocesses.
+          { _as_can_reexec=; unset _as_can_reexec;}
+if test "x$CONFIG_SHELL" = x; then
+  as_bourne_compatible="as_nop=:
+if test \${ZSH_VERSION+y} && (emulate sh) >/dev/null 2>&1
+then :
+  emulate sh
+  NULLCMD=:
+  # Pre-4.2 versions of Zsh do word splitting on \${1+\"\$@\"}, which
+  # is contrary to our usage.  Disable this feature.
+  alias -g '\${1+\"\$@\"}'='\"\$@\"'
+  setopt NO_GLOB_SUBST
+else \$as_nop
+  case \`(set -o) 2>/dev/null\` in #(
+  *posix*) :
+    set -o posix ;; #(
+  *) :
+     ;;
+esac
+fi
+"
+  as_required="as_fn_return () { (exit \$1); }
+as_fn_success () { as_fn_return 0; }
+as_fn_failure () { as_fn_return 1; }
+as_fn_ret_success () { return 0; }
+as_fn_ret_failure () { return 1; }
+
+exitcode=0
+as_fn_success || { exitcode=1; echo as_fn_success failed.; }
+as_fn_failure && { exitcode=1; echo as_fn_failure succeeded.; }
+as_fn_ret_success || { exitcode=1; echo as_fn_ret_success failed.; }
+as_fn_ret_failure && { exitcode=1; echo as_fn_ret_failure succeeded.; }
+if ( set x; as_fn_ret_success y && test x = \"\$1\" )
+then :
+
+else \$as_nop
+  exitcode=1; echo positional parameters were not saved.
+fi
+test x\$exitcode = x0 || exit 1
+blah=\$(echo \$(echo blah))
+test x\"\$blah\" = xblah || exit 1
+test -x / || exit 1"
+  as_suggested="  as_lineno_1=";as_suggested=$as_suggested$LINENO;as_suggested=$as_suggested" as_lineno_1a=\$LINENO
+  as_lineno_2=";as_suggested=$as_suggested$LINENO;as_suggested=$as_suggested" as_lineno_2a=\$LINENO
+  eval 'test \"x\$as_lineno_1'\$as_run'\" != \"x\$as_lineno_2'\$as_run'\" &&
+  test \"x\`expr \$as_lineno_1'\$as_run' + 1\`\" = \"x\$as_lineno_2'\$as_run'\"' || exit 1"
+  if (eval "$as_required") 2>/dev/null
+then :
+  as_have_required=yes
+else $as_nop
+  as_have_required=no
+fi
+  if test x$as_have_required = xyes && (eval "$as_suggested") 2>/dev/null
+then :
+
+else $as_nop
+  as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+as_found=false
+for as_dir in /bin$PATH_SEPARATOR/usr/bin$PATH_SEPARATOR$PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+  as_found=:
+  case $as_dir in #(
+	 /*)
+	   for as_base in sh bash ksh sh5; do
+	     # Try only shells that exist, to save several forks.
+	     as_shell=$as_dir$as_base
+	     if { test -f "$as_shell" || test -f "$as_shell.exe"; } &&
+		    as_run=a "$as_shell" -c "$as_bourne_compatible""$as_required" 2>/dev/null
+then :
+  CONFIG_SHELL=$as_shell as_have_required=yes
+		   if as_run=a "$as_shell" -c "$as_bourne_compatible""$as_suggested" 2>/dev/null
+then :
+  break 2
+fi
+fi
+	   done;;
+       esac
+  as_found=false
+done
+IFS=$as_save_IFS
+if $as_found
+then :
+
+else $as_nop
+  if { test -f "$SHELL" || test -f "$SHELL.exe"; } &&
+	      as_run=a "$SHELL" -c "$as_bourne_compatible""$as_required" 2>/dev/null
+then :
+  CONFIG_SHELL=$SHELL as_have_required=yes
+fi
+fi
+
+
+      if test "x$CONFIG_SHELL" != x
+then :
+  export CONFIG_SHELL
+             # We cannot yet assume a decent shell, so we have to provide a
+# neutralization value for shells without unset; and this also
+# works around shells that cannot unset nonexistent variables.
+# Preserve -v and -x to the replacement shell.
+BASH_ENV=/dev/null
+ENV=/dev/null
+(unset BASH_ENV) >/dev/null 2>&1 && unset BASH_ENV ENV
+case $- in # ((((
+  *v*x* | *x*v* ) as_opts=-vx ;;
+  *v* ) as_opts=-v ;;
+  *x* ) as_opts=-x ;;
+  * ) as_opts= ;;
+esac
+exec $CONFIG_SHELL $as_opts "$as_myself" ${1+"$@"}
+# Admittedly, this is quite paranoid, since all the known shells bail
+# out after a failed `exec'.
+printf "%s\n" "$0: could not re-execute with $CONFIG_SHELL" >&2
+exit 255
+fi
+
+    if test x$as_have_required = xno
+then :
+  printf "%s\n" "$0: This script requires a shell more modern than all"
+  printf "%s\n" "$0: the shells that I found on your system."
+  if test ${ZSH_VERSION+y} ; then
+    printf "%s\n" "$0: In particular, zsh $ZSH_VERSION has bugs and should"
+    printf "%s\n" "$0: be upgraded to zsh 4.3.4 or later."
+  else
+    printf "%s\n" "$0: Please tell bug-autoconf@gnu.org and
+$0: streamly@composewell.com about your system, including
+$0: any error possibly output before this message. Then
+$0: install a modern shell, or manually run the script
+$0: under such a shell if you do have one."
+  fi
+  exit 1
+fi
+fi
+fi
+SHELL=${CONFIG_SHELL-/bin/sh}
+export SHELL
+# Unset more variables known to interfere with behavior of common tools.
+CLICOLOR_FORCE= GREP_OPTIONS=
+unset CLICOLOR_FORCE GREP_OPTIONS
+
+## --------------------- ##
+## M4sh Shell Functions. ##
+## --------------------- ##
+# as_fn_unset VAR
+# ---------------
+# Portably unset VAR.
+as_fn_unset ()
+{
+  { eval $1=; unset $1;}
+}
+as_unset=as_fn_unset
+
+
+# as_fn_set_status STATUS
+# -----------------------
+# Set $? to STATUS, without forking.
+as_fn_set_status ()
+{
+  return $1
+} # as_fn_set_status
+
+# as_fn_exit STATUS
+# -----------------
+# Exit the shell with STATUS, even in a "trap 0" or "set -e" context.
+as_fn_exit ()
+{
+  set +e
+  as_fn_set_status $1
+  exit $1
+} # as_fn_exit
+# as_fn_nop
+# ---------
+# Do nothing but, unlike ":", preserve the value of $?.
+as_fn_nop ()
+{
+  return $?
+}
+as_nop=as_fn_nop
+
+# as_fn_mkdir_p
+# -------------
+# Create "$as_dir" as a directory, including parents if necessary.
+as_fn_mkdir_p ()
+{
+
+  case $as_dir in #(
+  -*) as_dir=./$as_dir;;
+  esac
+  test -d "$as_dir" || eval $as_mkdir_p || {
+    as_dirs=
+    while :; do
+      case $as_dir in #(
+      *\'*) as_qdir=`printf "%s\n" "$as_dir" | sed "s/'/'\\\\\\\\''/g"`;; #'(
+      *) as_qdir=$as_dir;;
+      esac
+      as_dirs="'$as_qdir' $as_dirs"
+      as_dir=`$as_dirname -- "$as_dir" ||
+$as_expr X"$as_dir" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
+	 X"$as_dir" : 'X\(//\)[^/]' \| \
+	 X"$as_dir" : 'X\(//\)$' \| \
+	 X"$as_dir" : 'X\(/\)' \| . 2>/dev/null ||
+printf "%s\n" X"$as_dir" |
+    sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)[^/].*/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+      test -d "$as_dir" && break
+    done
+    test -z "$as_dirs" || eval "mkdir $as_dirs"
+  } || test -d "$as_dir" || as_fn_error $? "cannot create directory $as_dir"
+
+
+} # as_fn_mkdir_p
+
+# as_fn_executable_p FILE
+# -----------------------
+# Test if FILE is an executable regular file.
+as_fn_executable_p ()
+{
+  test -f "$1" && test -x "$1"
+} # as_fn_executable_p
+# as_fn_append VAR VALUE
+# ----------------------
+# Append the text in VALUE to the end of the definition contained in VAR. Take
+# advantage of any shell optimizations that allow amortized linear growth over
+# repeated appends, instead of the typical quadratic growth present in naive
+# implementations.
+if (eval "as_var=1; as_var+=2; test x\$as_var = x12") 2>/dev/null
+then :
+  eval 'as_fn_append ()
+  {
+    eval $1+=\$2
+  }'
+else $as_nop
+  as_fn_append ()
+  {
+    eval $1=\$$1\$2
+  }
+fi # as_fn_append
+
+# as_fn_arith ARG...
+# ------------------
+# Perform arithmetic evaluation on the ARGs, and store the result in the
+# global $as_val. Take advantage of shells that can avoid forks. The arguments
+# must be portable across $(()) and expr.
+if (eval "test \$(( 1 + 1 )) = 2") 2>/dev/null
+then :
+  eval 'as_fn_arith ()
+  {
+    as_val=$(( $* ))
+  }'
+else $as_nop
+  as_fn_arith ()
+  {
+    as_val=`expr "$@" || test $? -eq 1`
+  }
+fi # as_fn_arith
+
+# as_fn_nop
+# ---------
+# Do nothing but, unlike ":", preserve the value of $?.
+as_fn_nop ()
+{
+  return $?
+}
+as_nop=as_fn_nop
+
+# as_fn_error STATUS ERROR [LINENO LOG_FD]
+# ----------------------------------------
+# Output "`basename $0`: error: ERROR" to stderr. If LINENO and LOG_FD are
+# provided, also output the error to LOG_FD, referencing LINENO. Then exit the
+# script with STATUS, using 1 if that was 0.
+as_fn_error ()
+{
+  as_status=$1; test $as_status -eq 0 && as_status=1
+  if test "$4"; then
+    as_lineno=${as_lineno-"$3"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: $2" >&$4
+  fi
+  printf "%s\n" "$as_me: error: $2" >&2
+  as_fn_exit $as_status
+} # as_fn_error
+
+if expr a : '\(a\)' >/dev/null 2>&1 &&
+   test "X`expr 00001 : '.*\(...\)'`" = X001; then
+  as_expr=expr
+else
+  as_expr=false
+fi
+
+if (basename -- /) >/dev/null 2>&1 && test "X`basename -- / 2>&1`" = "X/"; then
+  as_basename=basename
+else
+  as_basename=false
+fi
+
+if (as_dir=`dirname -- /` && test "X$as_dir" = X/) >/dev/null 2>&1; then
+  as_dirname=dirname
+else
+  as_dirname=false
+fi
+
+as_me=`$as_basename -- "$0" ||
+$as_expr X/"$0" : '.*/\([^/][^/]*\)/*$' \| \
+	 X"$0" : 'X\(//\)$' \| \
+	 X"$0" : 'X\(/\)' \| . 2>/dev/null ||
+printf "%s\n" X/"$0" |
+    sed '/^.*\/\([^/][^/]*\)\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\/\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\/\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+
+# Avoid depending upon Character Ranges.
+as_cr_letters='abcdefghijklmnopqrstuvwxyz'
+as_cr_LETTERS='ABCDEFGHIJKLMNOPQRSTUVWXYZ'
+as_cr_Letters=$as_cr_letters$as_cr_LETTERS
+as_cr_digits='0123456789'
+as_cr_alnum=$as_cr_Letters$as_cr_digits
+
+
+  as_lineno_1=$LINENO as_lineno_1a=$LINENO
+  as_lineno_2=$LINENO as_lineno_2a=$LINENO
+  eval 'test "x$as_lineno_1'$as_run'" != "x$as_lineno_2'$as_run'" &&
+  test "x`expr $as_lineno_1'$as_run' + 1`" = "x$as_lineno_2'$as_run'"' || {
+  # Blame Lee E. McMahon (1931-1989) for sed's syntax.  :-)
+  sed -n '
+    p
+    /[$]LINENO/=
+  ' <$as_myself |
+    sed '
+      s/[$]LINENO.*/&-/
+      t lineno
+      b
+      :lineno
+      N
+      :loop
+      s/[$]LINENO\([^'$as_cr_alnum'_].*\n\)\(.*\)/\2\1\2/
+      t loop
+      s/-\n.*//
+    ' >$as_me.lineno &&
+  chmod +x "$as_me.lineno" ||
+    { printf "%s\n" "$as_me: error: cannot create $as_me.lineno; rerun with a POSIX shell" >&2; as_fn_exit 1; }
+
+  # If we had to re-execute with $CONFIG_SHELL, we're ensured to have
+  # already done that, so ensure we don't try to do so again and fall
+  # in an infinite loop.  This has already happened in practice.
+  _as_can_reexec=no; export _as_can_reexec
+  # Don't try to exec as it changes $[0], causing all sort of problems
+  # (the dirname of $[0] is not the place where we might find the
+  # original and so on.  Autoconf is especially sensitive to this).
+  . "./$as_me.lineno"
+  # Exit status is that of the last command.
+  exit
+}
+
+
+# Determine whether it's possible to make 'echo' print without a newline.
+# These variables are no longer used directly by Autoconf, but are AC_SUBSTed
+# for compatibility with existing Makefiles.
+ECHO_C= ECHO_N= ECHO_T=
+case `echo -n x` in #(((((
+-n*)
+  case `echo 'xy\c'` in
+  *c*) ECHO_T='	';;	# ECHO_T is single tab character.
+  xy)  ECHO_C='\c';;
+  *)   echo `echo ksh88 bug on AIX 6.1` > /dev/null
+       ECHO_T='	';;
+  esac;;
+*)
+  ECHO_N='-n';;
+esac
+
+# For backward compatibility with old third-party macros, we provide
+# the shell variables $as_echo and $as_echo_n.  New code should use
+# AS_ECHO(["message"]) and AS_ECHO_N(["message"]), respectively.
+as_echo='printf %s\n'
+as_echo_n='printf %s'
+
+
+rm -f conf$$ conf$$.exe conf$$.file
+if test -d conf$$.dir; then
+  rm -f conf$$.dir/conf$$.file
+else
+  rm -f conf$$.dir
+  mkdir conf$$.dir 2>/dev/null
+fi
+if (echo >conf$$.file) 2>/dev/null; then
+  if ln -s conf$$.file conf$$ 2>/dev/null; then
+    as_ln_s='ln -s'
+    # ... but there are two gotchas:
+    # 1) On MSYS, both `ln -s file dir' and `ln file dir' fail.
+    # 2) DJGPP < 2.04 has no symlinks; `ln -s' creates a wrapper executable.
+    # In both cases, we have to default to `cp -pR'.
+    ln -s conf$$.file conf$$.dir 2>/dev/null && test ! -f conf$$.exe ||
+      as_ln_s='cp -pR'
+  elif ln conf$$.file conf$$ 2>/dev/null; then
+    as_ln_s=ln
+  else
+    as_ln_s='cp -pR'
+  fi
+else
+  as_ln_s='cp -pR'
+fi
+rm -f conf$$ conf$$.exe conf$$.dir/conf$$.file conf$$.file
+rmdir conf$$.dir 2>/dev/null
+
+if mkdir -p . 2>/dev/null; then
+  as_mkdir_p='mkdir -p "$as_dir"'
+else
+  test -d ./-p && rmdir ./-p
+  as_mkdir_p=false
+fi
+
+as_test_x='test -x'
+as_executable_p=as_fn_executable_p
+
+# Sed expression to map a string onto a valid CPP name.
+as_tr_cpp="eval sed 'y%*$as_cr_letters%P$as_cr_LETTERS%;s%[^_$as_cr_alnum]%_%g'"
+
+# Sed expression to map a string onto a valid variable name.
+as_tr_sh="eval sed 'y%*+%pp%;s%[^_$as_cr_alnum]%_%g'"
+
+
+test -n "$DJDIR" || exec 7<&0 </dev/null
+exec 6>&1
+
+# Name of the host.
+# hostname on some systems (SVR3.2, old GNU/Linux) returns a bogus exit status,
+# so uname gets run too.
+ac_hostname=`(hostname || uname -n) 2>/dev/null | sed 1q`
+
+#
+# Initializations.
+#
+ac_default_prefix=/usr/local
+ac_clean_files=
+ac_config_libobj_dir=.
+LIBOBJS=
+cross_compiling=no
+subdirs=
+MFLAGS=
+MAKEFLAGS=
+
+# Identity of this package.
+PACKAGE_NAME='streamly'
+PACKAGE_TARNAME='streamly'
+PACKAGE_VERSION='0.11.0'
+PACKAGE_STRING='streamly 0.11.0'
+PACKAGE_BUGREPORT='streamly@composewell.com'
+PACKAGE_URL='https://streamly.composewell.com'
+
+ac_subst_vars='LTLIBOBJS
+LIBOBJS
+OBJEXT
+EXEEXT
+ac_ct_CC
+CPPFLAGS
+LDFLAGS
+CFLAGS
+CC
+target_alias
+host_alias
+build_alias
+LIBS
+ECHO_T
+ECHO_N
+ECHO_C
+DEFS
+mandir
+localedir
+libdir
+psdir
+pdfdir
+dvidir
+htmldir
+infodir
+docdir
+oldincludedir
+includedir
+runstatedir
+localstatedir
+sharedstatedir
+sysconfdir
+datadir
+datarootdir
+libexecdir
+sbindir
+bindir
+program_transform_name
+prefix
+exec_prefix
+PACKAGE_URL
+PACKAGE_BUGREPORT
+PACKAGE_STRING
+PACKAGE_VERSION
+PACKAGE_TARNAME
+PACKAGE_NAME
+PATH_SEPARATOR
+SHELL'
+ac_subst_files=''
+ac_user_opts='
+enable_option_checking
+with_compiler
+'
+      ac_precious_vars='build_alias
+host_alias
+target_alias
+CC
+CFLAGS
+LDFLAGS
+LIBS
+CPPFLAGS'
+
+
+# Initialize some variables set by options.
+ac_init_help=
+ac_init_version=false
+ac_unrecognized_opts=
+ac_unrecognized_sep=
+# The variables have the same names as the options, with
+# dashes changed to underlines.
+cache_file=/dev/null
+exec_prefix=NONE
+no_create=
+no_recursion=
+prefix=NONE
+program_prefix=NONE
+program_suffix=NONE
+program_transform_name=s,x,x,
+silent=
+site=
+srcdir=
+verbose=
+x_includes=NONE
+x_libraries=NONE
+
+# Installation directory options.
+# These are left unexpanded so users can "make install exec_prefix=/foo"
+# and all the variables that are supposed to be based on exec_prefix
+# by default will actually change.
+# Use braces instead of parens because sh, perl, etc. also accept them.
+# (The list follows the same order as the GNU Coding Standards.)
+bindir='${exec_prefix}/bin'
+sbindir='${exec_prefix}/sbin'
+libexecdir='${exec_prefix}/libexec'
+datarootdir='${prefix}/share'
+datadir='${datarootdir}'
+sysconfdir='${prefix}/etc'
+sharedstatedir='${prefix}/com'
+localstatedir='${prefix}/var'
+runstatedir='${localstatedir}/run'
+includedir='${prefix}/include'
+oldincludedir='/usr/include'
+docdir='${datarootdir}/doc/${PACKAGE_TARNAME}'
+infodir='${datarootdir}/info'
+htmldir='${docdir}'
+dvidir='${docdir}'
+pdfdir='${docdir}'
+psdir='${docdir}'
+libdir='${exec_prefix}/lib'
+localedir='${datarootdir}/locale'
+mandir='${datarootdir}/man'
+
+ac_prev=
+ac_dashdash=
+for ac_option
+do
+  # If the previous option needs an argument, assign it.
+  if test -n "$ac_prev"; then
+    eval $ac_prev=\$ac_option
+    ac_prev=
+    continue
+  fi
+
+  case $ac_option in
+  *=?*) ac_optarg=`expr "X$ac_option" : '[^=]*=\(.*\)'` ;;
+  *=)   ac_optarg= ;;
+  *)    ac_optarg=yes ;;
+  esac
+
+  case $ac_dashdash$ac_option in
+  --)
+    ac_dashdash=yes ;;
+
+  -bindir | --bindir | --bindi | --bind | --bin | --bi)
+    ac_prev=bindir ;;
+  -bindir=* | --bindir=* | --bindi=* | --bind=* | --bin=* | --bi=*)
+    bindir=$ac_optarg ;;
+
+  -build | --build | --buil | --bui | --bu)
+    ac_prev=build_alias ;;
+  -build=* | --build=* | --buil=* | --bui=* | --bu=*)
+    build_alias=$ac_optarg ;;
+
+  -cache-file | --cache-file | --cache-fil | --cache-fi \
+  | --cache-f | --cache- | --cache | --cach | --cac | --ca | --c)
+    ac_prev=cache_file ;;
+  -cache-file=* | --cache-file=* | --cache-fil=* | --cache-fi=* \
+  | --cache-f=* | --cache-=* | --cache=* | --cach=* | --cac=* | --ca=* | --c=*)
+    cache_file=$ac_optarg ;;
+
+  --config-cache | -C)
+    cache_file=config.cache ;;
+
+  -datadir | --datadir | --datadi | --datad)
+    ac_prev=datadir ;;
+  -datadir=* | --datadir=* | --datadi=* | --datad=*)
+    datadir=$ac_optarg ;;
+
+  -datarootdir | --datarootdir | --datarootdi | --datarootd | --dataroot \
+  | --dataroo | --dataro | --datar)
+    ac_prev=datarootdir ;;
+  -datarootdir=* | --datarootdir=* | --datarootdi=* | --datarootd=* \
+  | --dataroot=* | --dataroo=* | --dataro=* | --datar=*)
+    datarootdir=$ac_optarg ;;
+
+  -disable-* | --disable-*)
+    ac_useropt=`expr "x$ac_option" : 'x-*disable-\(.*\)'`
+    # Reject names that are not valid shell variable names.
+    expr "x$ac_useropt" : ".*[^-+._$as_cr_alnum]" >/dev/null &&
+      as_fn_error $? "invalid feature name: \`$ac_useropt'"
+    ac_useropt_orig=$ac_useropt
+    ac_useropt=`printf "%s\n" "$ac_useropt" | sed 's/[-+.]/_/g'`
+    case $ac_user_opts in
+      *"
+"enable_$ac_useropt"
+"*) ;;
+      *) ac_unrecognized_opts="$ac_unrecognized_opts$ac_unrecognized_sep--disable-$ac_useropt_orig"
+	 ac_unrecognized_sep=', ';;
+    esac
+    eval enable_$ac_useropt=no ;;
+
+  -docdir | --docdir | --docdi | --doc | --do)
+    ac_prev=docdir ;;
+  -docdir=* | --docdir=* | --docdi=* | --doc=* | --do=*)
+    docdir=$ac_optarg ;;
+
+  -dvidir | --dvidir | --dvidi | --dvid | --dvi | --dv)
+    ac_prev=dvidir ;;
+  -dvidir=* | --dvidir=* | --dvidi=* | --dvid=* | --dvi=* | --dv=*)
+    dvidir=$ac_optarg ;;
+
+  -enable-* | --enable-*)
+    ac_useropt=`expr "x$ac_option" : 'x-*enable-\([^=]*\)'`
+    # Reject names that are not valid shell variable names.
+    expr "x$ac_useropt" : ".*[^-+._$as_cr_alnum]" >/dev/null &&
+      as_fn_error $? "invalid feature name: \`$ac_useropt'"
+    ac_useropt_orig=$ac_useropt
+    ac_useropt=`printf "%s\n" "$ac_useropt" | sed 's/[-+.]/_/g'`
+    case $ac_user_opts in
+      *"
+"enable_$ac_useropt"
+"*) ;;
+      *) ac_unrecognized_opts="$ac_unrecognized_opts$ac_unrecognized_sep--enable-$ac_useropt_orig"
+	 ac_unrecognized_sep=', ';;
+    esac
+    eval enable_$ac_useropt=\$ac_optarg ;;
+
+  -exec-prefix | --exec_prefix | --exec-prefix | --exec-prefi \
+  | --exec-pref | --exec-pre | --exec-pr | --exec-p | --exec- \
+  | --exec | --exe | --ex)
+    ac_prev=exec_prefix ;;
+  -exec-prefix=* | --exec_prefix=* | --exec-prefix=* | --exec-prefi=* \
+  | --exec-pref=* | --exec-pre=* | --exec-pr=* | --exec-p=* | --exec-=* \
+  | --exec=* | --exe=* | --ex=*)
+    exec_prefix=$ac_optarg ;;
+
+  -gas | --gas | --ga | --g)
+    # Obsolete; use --with-gas.
+    with_gas=yes ;;
+
+  -help | --help | --hel | --he | -h)
+    ac_init_help=long ;;
+  -help=r* | --help=r* | --hel=r* | --he=r* | -hr*)
+    ac_init_help=recursive ;;
+  -help=s* | --help=s* | --hel=s* | --he=s* | -hs*)
+    ac_init_help=short ;;
+
+  -host | --host | --hos | --ho)
+    ac_prev=host_alias ;;
+  -host=* | --host=* | --hos=* | --ho=*)
+    host_alias=$ac_optarg ;;
+
+  -htmldir | --htmldir | --htmldi | --htmld | --html | --htm | --ht)
+    ac_prev=htmldir ;;
+  -htmldir=* | --htmldir=* | --htmldi=* | --htmld=* | --html=* | --htm=* \
+  | --ht=*)
+    htmldir=$ac_optarg ;;
+
+  -includedir | --includedir | --includedi | --included | --include \
+  | --includ | --inclu | --incl | --inc)
+    ac_prev=includedir ;;
+  -includedir=* | --includedir=* | --includedi=* | --included=* | --include=* \
+  | --includ=* | --inclu=* | --incl=* | --inc=*)
+    includedir=$ac_optarg ;;
+
+  -infodir | --infodir | --infodi | --infod | --info | --inf)
+    ac_prev=infodir ;;
+  -infodir=* | --infodir=* | --infodi=* | --infod=* | --info=* | --inf=*)
+    infodir=$ac_optarg ;;
+
+  -libdir | --libdir | --libdi | --libd)
+    ac_prev=libdir ;;
+  -libdir=* | --libdir=* | --libdi=* | --libd=*)
+    libdir=$ac_optarg ;;
+
+  -libexecdir | --libexecdir | --libexecdi | --libexecd | --libexec \
+  | --libexe | --libex | --libe)
+    ac_prev=libexecdir ;;
+  -libexecdir=* | --libexecdir=* | --libexecdi=* | --libexecd=* | --libexec=* \
+  | --libexe=* | --libex=* | --libe=*)
+    libexecdir=$ac_optarg ;;
+
+  -localedir | --localedir | --localedi | --localed | --locale)
+    ac_prev=localedir ;;
+  -localedir=* | --localedir=* | --localedi=* | --localed=* | --locale=*)
+    localedir=$ac_optarg ;;
+
+  -localstatedir | --localstatedir | --localstatedi | --localstated \
+  | --localstate | --localstat | --localsta | --localst | --locals)
+    ac_prev=localstatedir ;;
+  -localstatedir=* | --localstatedir=* | --localstatedi=* | --localstated=* \
+  | --localstate=* | --localstat=* | --localsta=* | --localst=* | --locals=*)
+    localstatedir=$ac_optarg ;;
+
+  -mandir | --mandir | --mandi | --mand | --man | --ma | --m)
+    ac_prev=mandir ;;
+  -mandir=* | --mandir=* | --mandi=* | --mand=* | --man=* | --ma=* | --m=*)
+    mandir=$ac_optarg ;;
+
+  -nfp | --nfp | --nf)
+    # Obsolete; use --without-fp.
+    with_fp=no ;;
+
+  -no-create | --no-create | --no-creat | --no-crea | --no-cre \
+  | --no-cr | --no-c | -n)
+    no_create=yes ;;
+
+  -no-recursion | --no-recursion | --no-recursio | --no-recursi \
+  | --no-recurs | --no-recur | --no-recu | --no-rec | --no-re | --no-r)
+    no_recursion=yes ;;
+
+  -oldincludedir | --oldincludedir | --oldincludedi | --oldincluded \
+  | --oldinclude | --oldinclud | --oldinclu | --oldincl | --oldinc \
+  | --oldin | --oldi | --old | --ol | --o)
+    ac_prev=oldincludedir ;;
+  -oldincludedir=* | --oldincludedir=* | --oldincludedi=* | --oldincluded=* \
+  | --oldinclude=* | --oldinclud=* | --oldinclu=* | --oldincl=* | --oldinc=* \
+  | --oldin=* | --oldi=* | --old=* | --ol=* | --o=*)
+    oldincludedir=$ac_optarg ;;
+
+  -prefix | --prefix | --prefi | --pref | --pre | --pr | --p)
+    ac_prev=prefix ;;
+  -prefix=* | --prefix=* | --prefi=* | --pref=* | --pre=* | --pr=* | --p=*)
+    prefix=$ac_optarg ;;
+
+  -program-prefix | --program-prefix | --program-prefi | --program-pref \
+  | --program-pre | --program-pr | --program-p)
+    ac_prev=program_prefix ;;
+  -program-prefix=* | --program-prefix=* | --program-prefi=* \
+  | --program-pref=* | --program-pre=* | --program-pr=* | --program-p=*)
+    program_prefix=$ac_optarg ;;
+
+  -program-suffix | --program-suffix | --program-suffi | --program-suff \
+  | --program-suf | --program-su | --program-s)
+    ac_prev=program_suffix ;;
+  -program-suffix=* | --program-suffix=* | --program-suffi=* \
+  | --program-suff=* | --program-suf=* | --program-su=* | --program-s=*)
+    program_suffix=$ac_optarg ;;
+
+  -program-transform-name | --program-transform-name \
+  | --program-transform-nam | --program-transform-na \
+  | --program-transform-n | --program-transform- \
+  | --program-transform | --program-transfor \
+  | --program-transfo | --program-transf \
+  | --program-trans | --program-tran \
+  | --progr-tra | --program-tr | --program-t)
+    ac_prev=program_transform_name ;;
+  -program-transform-name=* | --program-transform-name=* \
+  | --program-transform-nam=* | --program-transform-na=* \
+  | --program-transform-n=* | --program-transform-=* \
+  | --program-transform=* | --program-transfor=* \
+  | --program-transfo=* | --program-transf=* \
+  | --program-trans=* | --program-tran=* \
+  | --progr-tra=* | --program-tr=* | --program-t=*)
+    program_transform_name=$ac_optarg ;;
+
+  -pdfdir | --pdfdir | --pdfdi | --pdfd | --pdf | --pd)
+    ac_prev=pdfdir ;;
+  -pdfdir=* | --pdfdir=* | --pdfdi=* | --pdfd=* | --pdf=* | --pd=*)
+    pdfdir=$ac_optarg ;;
+
+  -psdir | --psdir | --psdi | --psd | --ps)
+    ac_prev=psdir ;;
+  -psdir=* | --psdir=* | --psdi=* | --psd=* | --ps=*)
+    psdir=$ac_optarg ;;
+
+  -q | -quiet | --quiet | --quie | --qui | --qu | --q \
+  | -silent | --silent | --silen | --sile | --sil)
+    silent=yes ;;
+
+  -runstatedir | --runstatedir | --runstatedi | --runstated \
+  | --runstate | --runstat | --runsta | --runst | --runs \
+  | --run | --ru | --r)
+    ac_prev=runstatedir ;;
+  -runstatedir=* | --runstatedir=* | --runstatedi=* | --runstated=* \
+  | --runstate=* | --runstat=* | --runsta=* | --runst=* | --runs=* \
+  | --run=* | --ru=* | --r=*)
+    runstatedir=$ac_optarg ;;
+
+  -sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb)
+    ac_prev=sbindir ;;
+  -sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \
+  | --sbi=* | --sb=*)
+    sbindir=$ac_optarg ;;
+
+  -sharedstatedir | --sharedstatedir | --sharedstatedi \
+  | --sharedstated | --sharedstate | --sharedstat | --sharedsta \
+  | --sharedst | --shareds | --shared | --share | --shar \
+  | --sha | --sh)
+    ac_prev=sharedstatedir ;;
+  -sharedstatedir=* | --sharedstatedir=* | --sharedstatedi=* \
+  | --sharedstated=* | --sharedstate=* | --sharedstat=* | --sharedsta=* \
+  | --sharedst=* | --shareds=* | --shared=* | --share=* | --shar=* \
+  | --sha=* | --sh=*)
+    sharedstatedir=$ac_optarg ;;
+
+  -site | --site | --sit)
+    ac_prev=site ;;
+  -site=* | --site=* | --sit=*)
+    site=$ac_optarg ;;
+
+  -srcdir | --srcdir | --srcdi | --srcd | --src | --sr)
+    ac_prev=srcdir ;;
+  -srcdir=* | --srcdir=* | --srcdi=* | --srcd=* | --src=* | --sr=*)
+    srcdir=$ac_optarg ;;
+
+  -sysconfdir | --sysconfdir | --sysconfdi | --sysconfd | --sysconf \
+  | --syscon | --sysco | --sysc | --sys | --sy)
+    ac_prev=sysconfdir ;;
+  -sysconfdir=* | --sysconfdir=* | --sysconfdi=* | --sysconfd=* | --sysconf=* \
+  | --syscon=* | --sysco=* | --sysc=* | --sys=* | --sy=*)
+    sysconfdir=$ac_optarg ;;
+
+  -target | --target | --targe | --targ | --tar | --ta | --t)
+    ac_prev=target_alias ;;
+  -target=* | --target=* | --targe=* | --targ=* | --tar=* | --ta=* | --t=*)
+    target_alias=$ac_optarg ;;
+
+  -v | -verbose | --verbose | --verbos | --verbo | --verb)
+    verbose=yes ;;
+
+  -version | --version | --versio | --versi | --vers | -V)
+    ac_init_version=: ;;
+
+  -with-* | --with-*)
+    ac_useropt=`expr "x$ac_option" : 'x-*with-\([^=]*\)'`
+    # Reject names that are not valid shell variable names.
+    expr "x$ac_useropt" : ".*[^-+._$as_cr_alnum]" >/dev/null &&
+      as_fn_error $? "invalid package name: \`$ac_useropt'"
+    ac_useropt_orig=$ac_useropt
+    ac_useropt=`printf "%s\n" "$ac_useropt" | sed 's/[-+.]/_/g'`
+    case $ac_user_opts in
+      *"
+"with_$ac_useropt"
+"*) ;;
+      *) ac_unrecognized_opts="$ac_unrecognized_opts$ac_unrecognized_sep--with-$ac_useropt_orig"
+	 ac_unrecognized_sep=', ';;
+    esac
+    eval with_$ac_useropt=\$ac_optarg ;;
+
+  -without-* | --without-*)
+    ac_useropt=`expr "x$ac_option" : 'x-*without-\(.*\)'`
+    # Reject names that are not valid shell variable names.
+    expr "x$ac_useropt" : ".*[^-+._$as_cr_alnum]" >/dev/null &&
+      as_fn_error $? "invalid package name: \`$ac_useropt'"
+    ac_useropt_orig=$ac_useropt
+    ac_useropt=`printf "%s\n" "$ac_useropt" | sed 's/[-+.]/_/g'`
+    case $ac_user_opts in
+      *"
+"with_$ac_useropt"
+"*) ;;
+      *) ac_unrecognized_opts="$ac_unrecognized_opts$ac_unrecognized_sep--without-$ac_useropt_orig"
+	 ac_unrecognized_sep=', ';;
+    esac
+    eval with_$ac_useropt=no ;;
+
+  --x)
+    # Obsolete; use --with-x.
+    with_x=yes ;;
+
+  -x-includes | --x-includes | --x-include | --x-includ | --x-inclu \
+  | --x-incl | --x-inc | --x-in | --x-i)
+    ac_prev=x_includes ;;
+  -x-includes=* | --x-includes=* | --x-include=* | --x-includ=* | --x-inclu=* \
+  | --x-incl=* | --x-inc=* | --x-in=* | --x-i=*)
+    x_includes=$ac_optarg ;;
+
+  -x-libraries | --x-libraries | --x-librarie | --x-librari \
+  | --x-librar | --x-libra | --x-libr | --x-lib | --x-li | --x-l)
+    ac_prev=x_libraries ;;
+  -x-libraries=* | --x-libraries=* | --x-librarie=* | --x-librari=* \
+  | --x-librar=* | --x-libra=* | --x-libr=* | --x-lib=* | --x-li=* | --x-l=*)
+    x_libraries=$ac_optarg ;;
+
+  -*) as_fn_error $? "unrecognized option: \`$ac_option'
+Try \`$0 --help' for more information"
+    ;;
+
+  *=*)
+    ac_envvar=`expr "x$ac_option" : 'x\([^=]*\)='`
+    # Reject names that are not valid shell variable names.
+    case $ac_envvar in #(
+      '' | [0-9]* | *[!_$as_cr_alnum]* )
+      as_fn_error $? "invalid variable name: \`$ac_envvar'" ;;
+    esac
+    eval $ac_envvar=\$ac_optarg
+    export $ac_envvar ;;
+
+  *)
+    # FIXME: should be removed in autoconf 3.0.
+    printf "%s\n" "$as_me: WARNING: you should use --build, --host, --target" >&2
+    expr "x$ac_option" : ".*[^-._$as_cr_alnum]" >/dev/null &&
+      printf "%s\n" "$as_me: WARNING: invalid host type: $ac_option" >&2
+    : "${build_alias=$ac_option} ${host_alias=$ac_option} ${target_alias=$ac_option}"
+    ;;
+
+  esac
+done
+
+if test -n "$ac_prev"; then
+  ac_option=--`echo $ac_prev | sed 's/_/-/g'`
+  as_fn_error $? "missing argument to $ac_option"
+fi
+
+if test -n "$ac_unrecognized_opts"; then
+  case $enable_option_checking in
+    no) ;;
+    fatal) as_fn_error $? "unrecognized options: $ac_unrecognized_opts" ;;
+    *)     printf "%s\n" "$as_me: WARNING: unrecognized options: $ac_unrecognized_opts" >&2 ;;
+  esac
+fi
+
+# Check all directory arguments for consistency.
+for ac_var in	exec_prefix prefix bindir sbindir libexecdir datarootdir \
+		datadir sysconfdir sharedstatedir localstatedir includedir \
+		oldincludedir docdir infodir htmldir dvidir pdfdir psdir \
+		libdir localedir mandir runstatedir
+do
+  eval ac_val=\$$ac_var
+  # Remove trailing slashes.
+  case $ac_val in
+    */ )
+      ac_val=`expr "X$ac_val" : 'X\(.*[^/]\)' \| "X$ac_val" : 'X\(.*\)'`
+      eval $ac_var=\$ac_val;;
+  esac
+  # Be sure to have absolute directory names.
+  case $ac_val in
+    [\\/$]* | ?:[\\/]* )  continue;;
+    NONE | '' ) case $ac_var in *prefix ) continue;; esac;;
+  esac
+  as_fn_error $? "expected an absolute directory name for --$ac_var: $ac_val"
+done
+
+# There might be people who depend on the old broken behavior: `$host'
+# used to hold the argument of --host etc.
+# FIXME: To remove some day.
+build=$build_alias
+host=$host_alias
+target=$target_alias
+
+# FIXME: To remove some day.
+if test "x$host_alias" != x; then
+  if test "x$build_alias" = x; then
+    cross_compiling=maybe
+  elif test "x$build_alias" != "x$host_alias"; then
+    cross_compiling=yes
+  fi
+fi
+
+ac_tool_prefix=
+test -n "$host_alias" && ac_tool_prefix=$host_alias-
+
+test "$silent" = yes && exec 6>/dev/null
+
+
+ac_pwd=`pwd` && test -n "$ac_pwd" &&
+ac_ls_di=`ls -di .` &&
+ac_pwd_ls_di=`cd "$ac_pwd" && ls -di .` ||
+  as_fn_error $? "working directory cannot be determined"
+test "X$ac_ls_di" = "X$ac_pwd_ls_di" ||
+  as_fn_error $? "pwd does not report name of working directory"
+
+
+# Find the source files, if location was not specified.
+if test -z "$srcdir"; then
+  ac_srcdir_defaulted=yes
+  # Try the directory containing this script, then the parent directory.
+  ac_confdir=`$as_dirname -- "$as_myself" ||
+$as_expr X"$as_myself" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
+	 X"$as_myself" : 'X\(//\)[^/]' \| \
+	 X"$as_myself" : 'X\(//\)$' \| \
+	 X"$as_myself" : 'X\(/\)' \| . 2>/dev/null ||
+printf "%s\n" X"$as_myself" |
+    sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)[^/].*/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+  srcdir=$ac_confdir
+  if test ! -r "$srcdir/$ac_unique_file"; then
+    srcdir=..
+  fi
+else
+  ac_srcdir_defaulted=no
+fi
+if test ! -r "$srcdir/$ac_unique_file"; then
+  test "$ac_srcdir_defaulted" = yes && srcdir="$ac_confdir or .."
+  as_fn_error $? "cannot find sources ($ac_unique_file) in $srcdir"
+fi
+ac_msg="sources are in $srcdir, but \`cd $srcdir' does not work"
+ac_abs_confdir=`(
+	cd "$srcdir" && test -r "./$ac_unique_file" || as_fn_error $? "$ac_msg"
+	pwd)`
+# When building in place, set srcdir=.
+if test "$ac_abs_confdir" = "$ac_pwd"; then
+  srcdir=.
+fi
+# Remove unnecessary trailing slashes from srcdir.
+# Double slashes in file names in object file debugging info
+# mess up M-x gdb in Emacs.
+case $srcdir in
+*/) srcdir=`expr "X$srcdir" : 'X\(.*[^/]\)' \| "X$srcdir" : 'X\(.*\)'`;;
+esac
+for ac_var in $ac_precious_vars; do
+  eval ac_env_${ac_var}_set=\${${ac_var}+set}
+  eval ac_env_${ac_var}_value=\$${ac_var}
+  eval ac_cv_env_${ac_var}_set=\${${ac_var}+set}
+  eval ac_cv_env_${ac_var}_value=\$${ac_var}
+done
+
+#
+# Report the --help message.
+#
+if test "$ac_init_help" = "long"; then
+  # Omit some internal or obsolete options to make the list less imposing.
+  # This message is too long to be a string in the A/UX 3.1 sh.
+  cat <<_ACEOF
+\`configure' configures streamly 0.11.0 to adapt to many kinds of systems.
+
+Usage: $0 [OPTION]... [VAR=VALUE]...
+
+To assign environment variables (e.g., CC, CFLAGS...), specify them as
+VAR=VALUE.  See below for descriptions of some of the useful variables.
+
+Defaults for the options are specified in brackets.
+
+Configuration:
+  -h, --help              display this help and exit
+      --help=short        display options specific to this package
+      --help=recursive    display the short help of all the included packages
+  -V, --version           display version information and exit
+  -q, --quiet, --silent   do not print \`checking ...' messages
+      --cache-file=FILE   cache test results in FILE [disabled]
+  -C, --config-cache      alias for \`--cache-file=config.cache'
+  -n, --no-create         do not create output files
+      --srcdir=DIR        find the sources in DIR [configure dir or \`..']
+
+Installation directories:
+  --prefix=PREFIX         install architecture-independent files in PREFIX
+                          [$ac_default_prefix]
+  --exec-prefix=EPREFIX   install architecture-dependent files in EPREFIX
+                          [PREFIX]
+
+By default, \`make install' will install all the files in
+\`$ac_default_prefix/bin', \`$ac_default_prefix/lib' etc.  You can specify
+an installation prefix other than \`$ac_default_prefix' using \`--prefix',
+for instance \`--prefix=\$HOME'.
+
+For better control, use the options below.
+
+Fine tuning of the installation directories:
+  --bindir=DIR            user executables [EPREFIX/bin]
+  --sbindir=DIR           system admin executables [EPREFIX/sbin]
+  --libexecdir=DIR        program executables [EPREFIX/libexec]
+  --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]
+  --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
+  --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
+  --runstatedir=DIR       modifiable per-process data [LOCALSTATEDIR/run]
+  --libdir=DIR            object code libraries [EPREFIX/lib]
+  --includedir=DIR        C header files [PREFIX/include]
+  --oldincludedir=DIR     C header files for non-gcc [/usr/include]
+  --datarootdir=DIR       read-only arch.-independent data root [PREFIX/share]
+  --datadir=DIR           read-only architecture-independent data [DATAROOTDIR]
+  --infodir=DIR           info documentation [DATAROOTDIR/info]
+  --localedir=DIR         locale-dependent data [DATAROOTDIR/locale]
+  --mandir=DIR            man documentation [DATAROOTDIR/man]
+  --docdir=DIR            documentation root [DATAROOTDIR/doc/streamly]
+  --htmldir=DIR           html documentation [DOCDIR]
+  --dvidir=DIR            dvi documentation [DOCDIR]
+  --pdfdir=DIR            pdf documentation [DOCDIR]
+  --psdir=DIR             ps documentation [DOCDIR]
+_ACEOF
+
+  cat <<\_ACEOF
+_ACEOF
+fi
+
+if test -n "$ac_init_help"; then
+  case $ac_init_help in
+     short | recursive ) echo "Configuration of streamly 0.11.0:";;
+   esac
+  cat <<\_ACEOF
+
+Optional Packages:
+  --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
+  --without-PACKAGE       do not use PACKAGE (same as --with-PACKAGE=no)
+GHC
+
+Some influential environment variables:
+  CC          C compiler command
+  CFLAGS      C compiler flags
+  LDFLAGS     linker flags, e.g. -L<lib dir> if you have libraries in a
+              nonstandard directory <lib dir>
+  LIBS        libraries to pass to the linker, e.g. -l<library>
+  CPPFLAGS    (Objective) C/C++ preprocessor flags, e.g. -I<include dir> if
+              you have headers in a nonstandard directory <include dir>
+
+Use these variables to override the choices made by `configure' or to help
+it to find libraries and programs with nonstandard names/locations.
+
+Report bugs to <streamly@composewell.com>.
+streamly home page: <https://streamly.composewell.com>.
+_ACEOF
+ac_status=$?
+fi
+
+if test "$ac_init_help" = "recursive"; then
+  # If there are subdirs, report their specific --help.
+  for ac_dir in : $ac_subdirs_all; do test "x$ac_dir" = x: && continue
+    test -d "$ac_dir" ||
+      { cd "$srcdir" && ac_pwd=`pwd` && srcdir=. && test -d "$ac_dir"; } ||
+      continue
+    ac_builddir=.
+
+case "$ac_dir" in
+.) ac_dir_suffix= ac_top_builddir_sub=. ac_top_build_prefix= ;;
+*)
+  ac_dir_suffix=/`printf "%s\n" "$ac_dir" | sed 's|^\.[\\/]||'`
+  # A ".." for each directory in $ac_dir_suffix.
+  ac_top_builddir_sub=`printf "%s\n" "$ac_dir_suffix" | sed 's|/[^\\/]*|/..|g;s|/||'`
+  case $ac_top_builddir_sub in
+  "") ac_top_builddir_sub=. ac_top_build_prefix= ;;
+  *)  ac_top_build_prefix=$ac_top_builddir_sub/ ;;
+  esac ;;
+esac
+ac_abs_top_builddir=$ac_pwd
+ac_abs_builddir=$ac_pwd$ac_dir_suffix
+# for backward compatibility:
+ac_top_builddir=$ac_top_build_prefix
+
+case $srcdir in
+  .)  # We are building in place.
+    ac_srcdir=.
+    ac_top_srcdir=$ac_top_builddir_sub
+    ac_abs_top_srcdir=$ac_pwd ;;
+  [\\/]* | ?:[\\/]* )  # Absolute name.
+    ac_srcdir=$srcdir$ac_dir_suffix;
+    ac_top_srcdir=$srcdir
+    ac_abs_top_srcdir=$srcdir ;;
+  *) # Relative name.
+    ac_srcdir=$ac_top_build_prefix$srcdir$ac_dir_suffix
+    ac_top_srcdir=$ac_top_build_prefix$srcdir
+    ac_abs_top_srcdir=$ac_pwd/$srcdir ;;
+esac
+ac_abs_srcdir=$ac_abs_top_srcdir$ac_dir_suffix
+
+    cd "$ac_dir" || { ac_status=$?; continue; }
+    # Check for configure.gnu first; this name is used for a wrapper for
+    # Metaconfig's "Configure" on case-insensitive file systems.
+    if test -f "$ac_srcdir/configure.gnu"; then
+      echo &&
+      $SHELL "$ac_srcdir/configure.gnu" --help=recursive
+    elif test -f "$ac_srcdir/configure"; then
+      echo &&
+      $SHELL "$ac_srcdir/configure" --help=recursive
+    else
+      printf "%s\n" "$as_me: WARNING: no configuration information is in $ac_dir" >&2
+    fi || ac_status=$?
+    cd "$ac_pwd" || { ac_status=$?; break; }
+  done
+fi
+
+test -n "$ac_init_help" && exit $ac_status
+if $ac_init_version; then
+  cat <<\_ACEOF
+streamly configure 0.11.0
+generated by GNU Autoconf 2.71
+
+Copyright (C) 2021 Free Software Foundation, Inc.
+This configure script is free software; the Free Software Foundation
+gives unlimited permission to copy, distribute and modify it.
+_ACEOF
+  exit
+fi
+
+## ------------------------ ##
+## Autoconf initialization. ##
+## ------------------------ ##
+
+# ac_fn_c_try_compile LINENO
+# --------------------------
+# Try to compile conftest.$ac_ext, and return whether this succeeded.
+ac_fn_c_try_compile ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  rm -f conftest.$ac_objext conftest.beam
+  if { { ac_try="$ac_compile"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+printf "%s\n" "$ac_try_echo"; } >&5
+  (eval "$ac_compile") 2>conftest.err
+  ac_status=$?
+  if test -s conftest.err; then
+    grep -v '^ *+' conftest.err >conftest.er1
+    cat conftest.er1 >&5
+    mv -f conftest.er1 conftest.err
+  fi
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; } && {
+	 test -z "$ac_c_werror_flag" ||
+	 test ! -s conftest.err
+       } && test -s conftest.$ac_objext
+then :
+  ac_retval=0
+else $as_nop
+  printf "%s\n" "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+	ac_retval=1
+fi
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+  as_fn_set_status $ac_retval
+
+} # ac_fn_c_try_compile
+
+# ac_fn_check_decl LINENO SYMBOL VAR INCLUDES EXTRA-OPTIONS FLAG-VAR
+# ------------------------------------------------------------------
+# Tests whether SYMBOL is declared in INCLUDES, setting cache variable VAR
+# accordingly. Pass EXTRA-OPTIONS to the compiler, using FLAG-VAR.
+ac_fn_check_decl ()
+{
+  as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+  as_decl_name=`echo $2|sed 's/ *(.*//'`
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether $as_decl_name is declared" >&5
+printf %s "checking whether $as_decl_name is declared... " >&6; }
+if eval test \${$3+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  as_decl_use=`echo $2|sed -e 's/(/((/' -e 's/)/) 0&/' -e 's/,/) 0& (/g'`
+  eval ac_save_FLAGS=\$$6
+  as_fn_append $6 " $5"
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+$4
+int
+main (void)
+{
+#ifndef $as_decl_name
+#ifdef __cplusplus
+  (void) $as_decl_use;
+#else
+  (void) $as_decl_name;
+#endif
+#endif
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  eval "$3=yes"
+else $as_nop
+  eval "$3=no"
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+  eval $6=\$ac_save_FLAGS
+
+fi
+eval ac_res=\$$3
+	       { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
+printf "%s\n" "$ac_res" >&6; }
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
+
+} # ac_fn_check_decl
+ac_configure_args_raw=
+for ac_arg
+do
+  case $ac_arg in
+  *\'*)
+    ac_arg=`printf "%s\n" "$ac_arg" | sed "s/'/'\\\\\\\\''/g"` ;;
+  esac
+  as_fn_append ac_configure_args_raw " '$ac_arg'"
+done
+
+case $ac_configure_args_raw in
+  *$as_nl*)
+    ac_safe_unquote= ;;
+  *)
+    ac_unsafe_z='|&;<>()$`\\"*?[ ''	' # This string ends in space, tab.
+    ac_unsafe_a="$ac_unsafe_z#~"
+    ac_safe_unquote="s/ '\\([^$ac_unsafe_a][^$ac_unsafe_z]*\\)'/ \\1/g"
+    ac_configure_args_raw=`      printf "%s\n" "$ac_configure_args_raw" | sed "$ac_safe_unquote"`;;
+esac
+
+cat >config.log <<_ACEOF
+This file contains any messages produced by compilers while
+running configure, to aid debugging if configure makes a mistake.
+
+It was created by streamly $as_me 0.11.0, which was
+generated by GNU Autoconf 2.71.  Invocation command line was
+
+  $ $0$ac_configure_args_raw
+
+_ACEOF
+exec 5>>config.log
+{
+cat <<_ASUNAME
+## --------- ##
+## Platform. ##
+## --------- ##
+
+hostname = `(hostname || uname -n) 2>/dev/null | sed 1q`
+uname -m = `(uname -m) 2>/dev/null || echo unknown`
+uname -r = `(uname -r) 2>/dev/null || echo unknown`
+uname -s = `(uname -s) 2>/dev/null || echo unknown`
+uname -v = `(uname -v) 2>/dev/null || echo unknown`
+
+/usr/bin/uname -p = `(/usr/bin/uname -p) 2>/dev/null || echo unknown`
+/bin/uname -X     = `(/bin/uname -X) 2>/dev/null     || echo unknown`
+
+/bin/arch              = `(/bin/arch) 2>/dev/null              || echo unknown`
+/usr/bin/arch -k       = `(/usr/bin/arch -k) 2>/dev/null       || echo unknown`
+/usr/convex/getsysinfo = `(/usr/convex/getsysinfo) 2>/dev/null || echo unknown`
+/usr/bin/hostinfo      = `(/usr/bin/hostinfo) 2>/dev/null      || echo unknown`
+/bin/machine           = `(/bin/machine) 2>/dev/null           || echo unknown`
+/usr/bin/oslevel       = `(/usr/bin/oslevel) 2>/dev/null       || echo unknown`
+/bin/universe          = `(/bin/universe) 2>/dev/null          || echo unknown`
+
+_ASUNAME
+
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    printf "%s\n" "PATH: $as_dir"
+  done
+IFS=$as_save_IFS
+
+} >&5
+
+cat >&5 <<_ACEOF
+
+
+## ----------- ##
+## Core tests. ##
+## ----------- ##
+
+_ACEOF
+
+
+# Keep a trace of the command line.
+# Strip out --no-create and --no-recursion so they do not pile up.
+# Strip out --silent because we don't want to record it for future runs.
+# Also quote any args containing shell meta-characters.
+# Make two passes to allow for proper duplicate-argument suppression.
+ac_configure_args=
+ac_configure_args0=
+ac_configure_args1=
+ac_must_keep_next=false
+for ac_pass in 1 2
+do
+  for ac_arg
+  do
+    case $ac_arg in
+    -no-create | --no-c* | -n | -no-recursion | --no-r*) continue ;;
+    -q | -quiet | --quiet | --quie | --qui | --qu | --q \
+    | -silent | --silent | --silen | --sile | --sil)
+      continue ;;
+    *\'*)
+      ac_arg=`printf "%s\n" "$ac_arg" | sed "s/'/'\\\\\\\\''/g"` ;;
+    esac
+    case $ac_pass in
+    1) as_fn_append ac_configure_args0 " '$ac_arg'" ;;
+    2)
+      as_fn_append ac_configure_args1 " '$ac_arg'"
+      if test $ac_must_keep_next = true; then
+	ac_must_keep_next=false # Got value, back to normal.
+      else
+	case $ac_arg in
+	  *=* | --config-cache | -C | -disable-* | --disable-* \
+	  | -enable-* | --enable-* | -gas | --g* | -nfp | --nf* \
+	  | -q | -quiet | --q* | -silent | --sil* | -v | -verb* \
+	  | -with-* | --with-* | -without-* | --without-* | --x)
+	    case "$ac_configure_args0 " in
+	      "$ac_configure_args1"*" '$ac_arg' "* ) continue ;;
+	    esac
+	    ;;
+	  -* ) ac_must_keep_next=true ;;
+	esac
+      fi
+      as_fn_append ac_configure_args " '$ac_arg'"
+      ;;
+    esac
+  done
+done
+{ ac_configure_args0=; unset ac_configure_args0;}
+{ ac_configure_args1=; unset ac_configure_args1;}
+
+# When interrupted or exit'd, cleanup temporary files, and complete
+# config.log.  We remove comments because anyway the quotes in there
+# would cause problems or look ugly.
+# WARNING: Use '\'' to represent an apostrophe within the trap.
+# WARNING: Do not start the trap code with a newline, due to a FreeBSD 4.0 bug.
+trap 'exit_status=$?
+  # Sanitize IFS.
+  IFS=" ""	$as_nl"
+  # Save into config.log some information that might help in debugging.
+  {
+    echo
+
+    printf "%s\n" "## ---------------- ##
+## Cache variables. ##
+## ---------------- ##"
+    echo
+    # The following way of writing the cache mishandles newlines in values,
+(
+  for ac_var in `(set) 2>&1 | sed -n '\''s/^\([a-zA-Z_][a-zA-Z0-9_]*\)=.*/\1/p'\''`; do
+    eval ac_val=\$$ac_var
+    case $ac_val in #(
+    *${as_nl}*)
+      case $ac_var in #(
+      *_cv_*) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: cache variable $ac_var contains a newline" >&5
+printf "%s\n" "$as_me: WARNING: cache variable $ac_var contains a newline" >&2;} ;;
+      esac
+      case $ac_var in #(
+      _ | IFS | as_nl) ;; #(
+      BASH_ARGV | BASH_SOURCE) eval $ac_var= ;; #(
+      *) { eval $ac_var=; unset $ac_var;} ;;
+      esac ;;
+    esac
+  done
+  (set) 2>&1 |
+    case $as_nl`(ac_space='\'' '\''; set) 2>&1` in #(
+    *${as_nl}ac_space=\ *)
+      sed -n \
+	"s/'\''/'\''\\\\'\'''\''/g;
+	  s/^\\([_$as_cr_alnum]*_cv_[_$as_cr_alnum]*\\)=\\(.*\\)/\\1='\''\\2'\''/p"
+      ;; #(
+    *)
+      sed -n "/^[_$as_cr_alnum]*_cv_[_$as_cr_alnum]*=/p"
+      ;;
+    esac |
+    sort
+)
+    echo
+
+    printf "%s\n" "## ----------------- ##
+## Output variables. ##
+## ----------------- ##"
+    echo
+    for ac_var in $ac_subst_vars
+    do
+      eval ac_val=\$$ac_var
+      case $ac_val in
+      *\'\''*) ac_val=`printf "%s\n" "$ac_val" | sed "s/'\''/'\''\\\\\\\\'\'''\''/g"`;;
+      esac
+      printf "%s\n" "$ac_var='\''$ac_val'\''"
+    done | sort
+    echo
+
+    if test -n "$ac_subst_files"; then
+      printf "%s\n" "## ------------------- ##
+## File substitutions. ##
+## ------------------- ##"
+      echo
+      for ac_var in $ac_subst_files
+      do
+	eval ac_val=\$$ac_var
+	case $ac_val in
+	*\'\''*) ac_val=`printf "%s\n" "$ac_val" | sed "s/'\''/'\''\\\\\\\\'\'''\''/g"`;;
+	esac
+	printf "%s\n" "$ac_var='\''$ac_val'\''"
+      done | sort
+      echo
+    fi
+
+    if test -s confdefs.h; then
+      printf "%s\n" "## ----------- ##
+## confdefs.h. ##
+## ----------- ##"
+      echo
+      cat confdefs.h
+      echo
+    fi
+    test "$ac_signal" != 0 &&
+      printf "%s\n" "$as_me: caught signal $ac_signal"
+    printf "%s\n" "$as_me: exit $exit_status"
+  } >&5
+  rm -f core *.core core.conftest.* &&
+    rm -f -r conftest* confdefs* conf$$* $ac_clean_files &&
+    exit $exit_status
+' 0
+for ac_signal in 1 2 13 15; do
+  trap 'ac_signal='$ac_signal'; as_fn_exit 1' $ac_signal
+done
+ac_signal=0
+
+# confdefs.h avoids OS command line length limits that DEFS can exceed.
+rm -f -r conftest* confdefs.h
+
+printf "%s\n" "/* confdefs.h */" > confdefs.h
+
+# Predefined preprocessor variables.
+
+printf "%s\n" "#define PACKAGE_NAME \"$PACKAGE_NAME\"" >>confdefs.h
+
+printf "%s\n" "#define PACKAGE_TARNAME \"$PACKAGE_TARNAME\"" >>confdefs.h
+
+printf "%s\n" "#define PACKAGE_VERSION \"$PACKAGE_VERSION\"" >>confdefs.h
+
+printf "%s\n" "#define PACKAGE_STRING \"$PACKAGE_STRING\"" >>confdefs.h
+
+printf "%s\n" "#define PACKAGE_BUGREPORT \"$PACKAGE_BUGREPORT\"" >>confdefs.h
+
+printf "%s\n" "#define PACKAGE_URL \"$PACKAGE_URL\"" >>confdefs.h
+
+
+# Let the site file select an alternate cache file if it wants to.
+# Prefer an explicitly selected file to automatically selected ones.
+if test -n "$CONFIG_SITE"; then
+  ac_site_files="$CONFIG_SITE"
+elif test "x$prefix" != xNONE; then
+  ac_site_files="$prefix/share/config.site $prefix/etc/config.site"
+else
+  ac_site_files="$ac_default_prefix/share/config.site $ac_default_prefix/etc/config.site"
+fi
+
+for ac_site_file in $ac_site_files
+do
+  case $ac_site_file in #(
+  */*) :
+     ;; #(
+  *) :
+    ac_site_file=./$ac_site_file ;;
+esac
+  if test -f "$ac_site_file" && test -r "$ac_site_file"; then
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: loading site script $ac_site_file" >&5
+printf "%s\n" "$as_me: loading site script $ac_site_file" >&6;}
+    sed 's/^/| /' "$ac_site_file" >&5
+    . "$ac_site_file" \
+      || { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "failed to load site script $ac_site_file
+See \`config.log' for more details" "$LINENO" 5; }
+  fi
+done
+
+if test -r "$cache_file"; then
+  # Some versions of bash will fail to source /dev/null (special files
+  # actually), so we avoid doing that.  DJGPP emulates it as a regular file.
+  if test /dev/null != "$cache_file" && test -f "$cache_file"; then
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: loading cache $cache_file" >&5
+printf "%s\n" "$as_me: loading cache $cache_file" >&6;}
+    case $cache_file in
+      [\\/]* | ?:[\\/]* ) . "$cache_file";;
+      *)                      . "./$cache_file";;
+    esac
+  fi
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: creating cache $cache_file" >&5
+printf "%s\n" "$as_me: creating cache $cache_file" >&6;}
+  >$cache_file
+fi
+
+# Test code for whether the C compiler supports C89 (global declarations)
+ac_c_conftest_c89_globals='
+/* Does the compiler advertise C89 conformance?
+   Do not test the value of __STDC__, because some compilers set it to 0
+   while being otherwise adequately conformant. */
+#if !defined __STDC__
+# error "Compiler does not advertise C89 conformance"
+#endif
+
+#include <stddef.h>
+#include <stdarg.h>
+struct stat;
+/* Most of the following tests are stolen from RCS 5.7 src/conf.sh.  */
+struct buf { int x; };
+struct buf * (*rcsopen) (struct buf *, struct stat *, int);
+static char *e (p, i)
+     char **p;
+     int i;
+{
+  return p[i];
+}
+static char *f (char * (*g) (char **, int), char **p, ...)
+{
+  char *s;
+  va_list v;
+  va_start (v,p);
+  s = g (p, va_arg (v,int));
+  va_end (v);
+  return s;
+}
+
+/* OSF 4.0 Compaq cc is some sort of almost-ANSI by default.  It has
+   function prototypes and stuff, but not \xHH hex character constants.
+   These do not provoke an error unfortunately, instead are silently treated
+   as an "x".  The following induces an error, until -std is added to get
+   proper ANSI mode.  Curiously \x00 != x always comes out true, for an
+   array size at least.  It is necessary to write \x00 == 0 to get something
+   that is true only with -std.  */
+int osf4_cc_array ['\''\x00'\'' == 0 ? 1 : -1];
+
+/* IBM C 6 for AIX is almost-ANSI by default, but it replaces macro parameters
+   inside strings and character constants.  */
+#define FOO(x) '\''x'\''
+int xlc6_cc_array[FOO(a) == '\''x'\'' ? 1 : -1];
+
+int test (int i, double x);
+struct s1 {int (*f) (int a);};
+struct s2 {int (*f) (double a);};
+int pairnames (int, char **, int *(*)(struct buf *, struct stat *, int),
+               int, int);'
+
+# Test code for whether the C compiler supports C89 (body of main).
+ac_c_conftest_c89_main='
+ok |= (argc == 0 || f (e, argv, 0) != argv[0] || f (e, argv, 1) != argv[1]);
+'
+
+# Test code for whether the C compiler supports C99 (global declarations)
+ac_c_conftest_c99_globals='
+// Does the compiler advertise C99 conformance?
+#if !defined __STDC_VERSION__ || __STDC_VERSION__ < 199901L
+# error "Compiler does not advertise C99 conformance"
+#endif
+
+#include <stdbool.h>
+extern int puts (const char *);
+extern int printf (const char *, ...);
+extern int dprintf (int, const char *, ...);
+extern void *malloc (size_t);
+
+// Check varargs macros.  These examples are taken from C99 6.10.3.5.
+// dprintf is used instead of fprintf to avoid needing to declare
+// FILE and stderr.
+#define debug(...) dprintf (2, __VA_ARGS__)
+#define showlist(...) puts (#__VA_ARGS__)
+#define report(test,...) ((test) ? puts (#test) : printf (__VA_ARGS__))
+static void
+test_varargs_macros (void)
+{
+  int x = 1234;
+  int y = 5678;
+  debug ("Flag");
+  debug ("X = %d\n", x);
+  showlist (The first, second, and third items.);
+  report (x>y, "x is %d but y is %d", x, y);
+}
+
+// Check long long types.
+#define BIG64 18446744073709551615ull
+#define BIG32 4294967295ul
+#define BIG_OK (BIG64 / BIG32 == 4294967297ull && BIG64 % BIG32 == 0)
+#if !BIG_OK
+  #error "your preprocessor is broken"
+#endif
+#if BIG_OK
+#else
+  #error "your preprocessor is broken"
+#endif
+static long long int bignum = -9223372036854775807LL;
+static unsigned long long int ubignum = BIG64;
+
+struct incomplete_array
+{
+  int datasize;
+  double data[];
+};
+
+struct named_init {
+  int number;
+  const wchar_t *name;
+  double average;
+};
+
+typedef const char *ccp;
+
+static inline int
+test_restrict (ccp restrict text)
+{
+  // See if C++-style comments work.
+  // Iterate through items via the restricted pointer.
+  // Also check for declarations in for loops.
+  for (unsigned int i = 0; *(text+i) != '\''\0'\''; ++i)
+    continue;
+  return 0;
+}
+
+// Check varargs and va_copy.
+static bool
+test_varargs (const char *format, ...)
+{
+  va_list args;
+  va_start (args, format);
+  va_list args_copy;
+  va_copy (args_copy, args);
+
+  const char *str = "";
+  int number = 0;
+  float fnumber = 0;
+
+  while (*format)
+    {
+      switch (*format++)
+	{
+	case '\''s'\'': // string
+	  str = va_arg (args_copy, const char *);
+	  break;
+	case '\''d'\'': // int
+	  number = va_arg (args_copy, int);
+	  break;
+	case '\''f'\'': // float
+	  fnumber = va_arg (args_copy, double);
+	  break;
+	default:
+	  break;
+	}
+    }
+  va_end (args_copy);
+  va_end (args);
+
+  return *str && number && fnumber;
+}
+'
+
+# Test code for whether the C compiler supports C99 (body of main).
+ac_c_conftest_c99_main='
+  // Check bool.
+  _Bool success = false;
+  success |= (argc != 0);
+
+  // Check restrict.
+  if (test_restrict ("String literal") == 0)
+    success = true;
+  char *restrict newvar = "Another string";
+
+  // Check varargs.
+  success &= test_varargs ("s, d'\'' f .", "string", 65, 34.234);
+  test_varargs_macros ();
+
+  // Check flexible array members.
+  struct incomplete_array *ia =
+    malloc (sizeof (struct incomplete_array) + (sizeof (double) * 10));
+  ia->datasize = 10;
+  for (int i = 0; i < ia->datasize; ++i)
+    ia->data[i] = i * 1.234;
+
+  // Check named initializers.
+  struct named_init ni = {
+    .number = 34,
+    .name = L"Test wide string",
+    .average = 543.34343,
+  };
+
+  ni.number = 58;
+
+  int dynamic_array[ni.number];
+  dynamic_array[0] = argv[0][0];
+  dynamic_array[ni.number - 1] = 543;
+
+  // work around unused variable warnings
+  ok |= (!success || bignum == 0LL || ubignum == 0uLL || newvar[0] == '\''x'\''
+	 || dynamic_array[ni.number - 1] != 543);
+'
+
+# Test code for whether the C compiler supports C11 (global declarations)
+ac_c_conftest_c11_globals='
+// Does the compiler advertise C11 conformance?
+#if !defined __STDC_VERSION__ || __STDC_VERSION__ < 201112L
+# error "Compiler does not advertise C11 conformance"
+#endif
+
+// Check _Alignas.
+char _Alignas (double) aligned_as_double;
+char _Alignas (0) no_special_alignment;
+extern char aligned_as_int;
+char _Alignas (0) _Alignas (int) aligned_as_int;
+
+// Check _Alignof.
+enum
+{
+  int_alignment = _Alignof (int),
+  int_array_alignment = _Alignof (int[100]),
+  char_alignment = _Alignof (char)
+};
+_Static_assert (0 < -_Alignof (int), "_Alignof is signed");
+
+// Check _Noreturn.
+int _Noreturn does_not_return (void) { for (;;) continue; }
+
+// Check _Static_assert.
+struct test_static_assert
+{
+  int x;
+  _Static_assert (sizeof (int) <= sizeof (long int),
+                  "_Static_assert does not work in struct");
+  long int y;
+};
+
+// Check UTF-8 literals.
+#define u8 syntax error!
+char const utf8_literal[] = u8"happens to be ASCII" "another string";
+
+// Check duplicate typedefs.
+typedef long *long_ptr;
+typedef long int *long_ptr;
+typedef long_ptr long_ptr;
+
+// Anonymous structures and unions -- taken from C11 6.7.2.1 Example 1.
+struct anonymous
+{
+  union {
+    struct { int i; int j; };
+    struct { int k; long int l; } w;
+  };
+  int m;
+} v1;
+'
+
+# Test code for whether the C compiler supports C11 (body of main).
+ac_c_conftest_c11_main='
+  _Static_assert ((offsetof (struct anonymous, i)
+		   == offsetof (struct anonymous, w.k)),
+		  "Anonymous union alignment botch");
+  v1.i = 2;
+  v1.w.k = 5;
+  ok |= v1.i != 5;
+'
+
+# Test code for whether the C compiler supports C11 (complete).
+ac_c_conftest_c11_program="${ac_c_conftest_c89_globals}
+${ac_c_conftest_c99_globals}
+${ac_c_conftest_c11_globals}
+
+int
+main (int argc, char **argv)
+{
+  int ok = 0;
+  ${ac_c_conftest_c89_main}
+  ${ac_c_conftest_c99_main}
+  ${ac_c_conftest_c11_main}
+  return ok;
+}
+"
+
+# Test code for whether the C compiler supports C99 (complete).
+ac_c_conftest_c99_program="${ac_c_conftest_c89_globals}
+${ac_c_conftest_c99_globals}
+
+int
+main (int argc, char **argv)
+{
+  int ok = 0;
+  ${ac_c_conftest_c89_main}
+  ${ac_c_conftest_c99_main}
+  return ok;
+}
+"
+
+# Test code for whether the C compiler supports C89 (complete).
+ac_c_conftest_c89_program="${ac_c_conftest_c89_globals}
+
+int
+main (int argc, char **argv)
+{
+  int ok = 0;
+  ${ac_c_conftest_c89_main}
+  return ok;
+}
+"
+
+# Check that the precious variables saved in the cache have kept the same
+# value.
+ac_cache_corrupted=false
+for ac_var in $ac_precious_vars; do
+  eval ac_old_set=\$ac_cv_env_${ac_var}_set
+  eval ac_new_set=\$ac_env_${ac_var}_set
+  eval ac_old_val=\$ac_cv_env_${ac_var}_value
+  eval ac_new_val=\$ac_env_${ac_var}_value
+  case $ac_old_set,$ac_new_set in
+    set,)
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: \`$ac_var' was set to \`$ac_old_val' in the previous run" >&5
+printf "%s\n" "$as_me: error: \`$ac_var' was set to \`$ac_old_val' in the previous run" >&2;}
+      ac_cache_corrupted=: ;;
+    ,set)
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: \`$ac_var' was not set in the previous run" >&5
+printf "%s\n" "$as_me: error: \`$ac_var' was not set in the previous run" >&2;}
+      ac_cache_corrupted=: ;;
+    ,);;
+    *)
+      if test "x$ac_old_val" != "x$ac_new_val"; then
+	# differences in whitespace do not lead to failure.
+	ac_old_val_w=`echo x $ac_old_val`
+	ac_new_val_w=`echo x $ac_new_val`
+	if test "$ac_old_val_w" != "$ac_new_val_w"; then
+	  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: \`$ac_var' has changed since the previous run:" >&5
+printf "%s\n" "$as_me: error: \`$ac_var' has changed since the previous run:" >&2;}
+	  ac_cache_corrupted=:
+	else
+	  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: warning: ignoring whitespace changes in \`$ac_var' since the previous run:" >&5
+printf "%s\n" "$as_me: warning: ignoring whitespace changes in \`$ac_var' since the previous run:" >&2;}
+	  eval $ac_var=\$ac_old_val
+	fi
+	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}:   former value:  \`$ac_old_val'" >&5
+printf "%s\n" "$as_me:   former value:  \`$ac_old_val'" >&2;}
+	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}:   current value: \`$ac_new_val'" >&5
+printf "%s\n" "$as_me:   current value: \`$ac_new_val'" >&2;}
+      fi;;
+  esac
+  # Pass precious variables to config.status.
+  if test "$ac_new_set" = set; then
+    case $ac_new_val in
+    *\'*) ac_arg=$ac_var=`printf "%s\n" "$ac_new_val" | sed "s/'/'\\\\\\\\''/g"` ;;
+    *) ac_arg=$ac_var=$ac_new_val ;;
+    esac
+    case " $ac_configure_args " in
+      *" '$ac_arg' "*) ;; # Avoid dups.  Use of quotes ensures accuracy.
+      *) as_fn_append ac_configure_args " '$ac_arg'" ;;
+    esac
+  fi
+done
+if $ac_cache_corrupted; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in \`$ac_pwd':" >&2;}
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: changes in the environment can compromise the build" >&5
+printf "%s\n" "$as_me: error: changes in the environment can compromise the build" >&2;}
+  as_fn_error $? "run \`${MAKE-make} distclean' and/or \`rm $cache_file'
+	    and start over" "$LINENO" 5
+fi
+## -------------------- ##
+## Main body of script. ##
+## -------------------- ##
+
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+
+
+# To suppress "WARNING: unrecognized options: --with-compiler"
+
+# Check whether --with-compiler was given.
+if test ${with_compiler+y}
+then :
+  withval=$with_compiler;
+fi
+
+
+# XXX Do this only for linux
+
+
+
+
+
+
+
+
+
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}gcc", so it can be a program name with args.
+set dummy ${ac_tool_prefix}gcc; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_CC+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  if test -n "$CC"; then
+  ac_cv_prog_CC="$CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_CC="${ac_tool_prefix}gcc"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+CC=$ac_cv_prog_CC
+if test -n "$CC"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $CC" >&5
+printf "%s\n" "$CC" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_CC"; then
+  ac_ct_CC=$CC
+  # Extract the first word of "gcc", so it can be a program name with args.
+set dummy gcc; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_CC+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  if test -n "$ac_ct_CC"; then
+  ac_cv_prog_ac_ct_CC="$ac_ct_CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_CC="gcc"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_CC=$ac_cv_prog_ac_ct_CC
+if test -n "$ac_ct_CC"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_CC" >&5
+printf "%s\n" "$ac_ct_CC" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_CC" = x; then
+    CC=""
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    CC=$ac_ct_CC
+  fi
+else
+  CC="$ac_cv_prog_CC"
+fi
+
+if test -z "$CC"; then
+          if test -n "$ac_tool_prefix"; then
+    # Extract the first word of "${ac_tool_prefix}cc", so it can be a program name with args.
+set dummy ${ac_tool_prefix}cc; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_CC+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  if test -n "$CC"; then
+  ac_cv_prog_CC="$CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_CC="${ac_tool_prefix}cc"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+CC=$ac_cv_prog_CC
+if test -n "$CC"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $CC" >&5
+printf "%s\n" "$CC" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+  fi
+fi
+if test -z "$CC"; then
+  # Extract the first word of "cc", so it can be a program name with args.
+set dummy cc; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_CC+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  if test -n "$CC"; then
+  ac_cv_prog_CC="$CC" # Let the user override the test.
+else
+  ac_prog_rejected=no
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    if test "$as_dir$ac_word$ac_exec_ext" = "/usr/ucb/cc"; then
+       ac_prog_rejected=yes
+       continue
+     fi
+    ac_cv_prog_CC="cc"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+if test $ac_prog_rejected = yes; then
+  # We found a bogon in the path, so make sure we never use it.
+  set dummy $ac_cv_prog_CC
+  shift
+  if test $# != 0; then
+    # We chose a different compiler from the bogus one.
+    # However, it has the same basename, so the bogon will be chosen
+    # first if we set CC to just the basename; use the full file name.
+    shift
+    ac_cv_prog_CC="$as_dir$ac_word${1+' '}$@"
+  fi
+fi
+fi
+fi
+CC=$ac_cv_prog_CC
+if test -n "$CC"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $CC" >&5
+printf "%s\n" "$CC" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$CC"; then
+  if test -n "$ac_tool_prefix"; then
+  for ac_prog in cl.exe
+  do
+    # Extract the first word of "$ac_tool_prefix$ac_prog", so it can be a program name with args.
+set dummy $ac_tool_prefix$ac_prog; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_CC+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  if test -n "$CC"; then
+  ac_cv_prog_CC="$CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_CC="$ac_tool_prefix$ac_prog"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+CC=$ac_cv_prog_CC
+if test -n "$CC"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $CC" >&5
+printf "%s\n" "$CC" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+    test -n "$CC" && break
+  done
+fi
+if test -z "$CC"; then
+  ac_ct_CC=$CC
+  for ac_prog in cl.exe
+do
+  # Extract the first word of "$ac_prog", so it can be a program name with args.
+set dummy $ac_prog; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_CC+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  if test -n "$ac_ct_CC"; then
+  ac_cv_prog_ac_ct_CC="$ac_ct_CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_CC="$ac_prog"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_CC=$ac_cv_prog_ac_ct_CC
+if test -n "$ac_ct_CC"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_CC" >&5
+printf "%s\n" "$ac_ct_CC" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+  test -n "$ac_ct_CC" && break
+done
+
+  if test "x$ac_ct_CC" = x; then
+    CC=""
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    CC=$ac_ct_CC
+  fi
+fi
+
+fi
+if test -z "$CC"; then
+  if test -n "$ac_tool_prefix"; then
+  # Extract the first word of "${ac_tool_prefix}clang", so it can be a program name with args.
+set dummy ${ac_tool_prefix}clang; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_CC+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  if test -n "$CC"; then
+  ac_cv_prog_CC="$CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_CC="${ac_tool_prefix}clang"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+CC=$ac_cv_prog_CC
+if test -n "$CC"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $CC" >&5
+printf "%s\n" "$CC" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+
+fi
+if test -z "$ac_cv_prog_CC"; then
+  ac_ct_CC=$CC
+  # Extract the first word of "clang", so it can be a program name with args.
+set dummy clang; ac_word=$2
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
+printf %s "checking for $ac_word... " >&6; }
+if test ${ac_cv_prog_ac_ct_CC+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  if test -n "$ac_ct_CC"; then
+  ac_cv_prog_ac_ct_CC="$ac_ct_CC" # Let the user override the test.
+else
+as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    for ac_exec_ext in '' $ac_executable_extensions; do
+  if as_fn_executable_p "$as_dir$ac_word$ac_exec_ext"; then
+    ac_cv_prog_ac_ct_CC="clang"
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: found $as_dir$ac_word$ac_exec_ext" >&5
+    break 2
+  fi
+done
+  done
+IFS=$as_save_IFS
+
+fi
+fi
+ac_ct_CC=$ac_cv_prog_ac_ct_CC
+if test -n "$ac_ct_CC"; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_ct_CC" >&5
+printf "%s\n" "$ac_ct_CC" >&6; }
+else
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+fi
+
+  if test "x$ac_ct_CC" = x; then
+    CC=""
+  else
+    case $cross_compiling:$ac_tool_warned in
+yes:)
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: using cross tools not prefixed with host triplet" >&5
+printf "%s\n" "$as_me: WARNING: using cross tools not prefixed with host triplet" >&2;}
+ac_tool_warned=yes ;;
+esac
+    CC=$ac_ct_CC
+  fi
+else
+  CC="$ac_cv_prog_CC"
+fi
+
+fi
+
+
+test -z "$CC" && { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "no acceptable C compiler found in \$PATH
+See \`config.log' for more details" "$LINENO" 5; }
+
+# Provide some information about the compiler.
+printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for C compiler version" >&5
+set X $ac_compile
+ac_compiler=$2
+for ac_option in --version -v -V -qversion -version; do
+  { { ac_try="$ac_compiler $ac_option >&5"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+printf "%s\n" "$ac_try_echo"; } >&5
+  (eval "$ac_compiler $ac_option >&5") 2>conftest.err
+  ac_status=$?
+  if test -s conftest.err; then
+    sed '10a\
+... rest of stderr output deleted ...
+         10q' conftest.err >conftest.er1
+    cat conftest.er1 >&5
+  fi
+  rm -f conftest.er1 conftest.err
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+done
+
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+ac_clean_files_save=$ac_clean_files
+ac_clean_files="$ac_clean_files a.out a.out.dSYM a.exe b.out"
+# Try to create an executable without -o first, disregard a.out.
+# It will help us diagnose broken compilers, and finding out an intuition
+# of exeext.
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether the C compiler works" >&5
+printf %s "checking whether the C compiler works... " >&6; }
+ac_link_default=`printf "%s\n" "$ac_link" | sed 's/ -o *conftest[^ ]*//'`
+
+# The possible output files:
+ac_files="a.out conftest.exe conftest a.exe a_out.exe b.out conftest.*"
+
+ac_rmfiles=
+for ac_file in $ac_files
+do
+  case $ac_file in
+    *.$ac_ext | *.xcoff | *.tds | *.d | *.pdb | *.xSYM | *.bb | *.bbg | *.map | *.inf | *.dSYM | *.o | *.obj ) ;;
+    * ) ac_rmfiles="$ac_rmfiles $ac_file";;
+  esac
+done
+rm -f $ac_rmfiles
+
+if { { ac_try="$ac_link_default"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+printf "%s\n" "$ac_try_echo"; } >&5
+  (eval "$ac_link_default") 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+then :
+  # Autoconf-2.13 could set the ac_cv_exeext variable to `no'.
+# So ignore a value of `no', otherwise this would lead to `EXEEXT = no'
+# in a Makefile.  We should not override ac_cv_exeext if it was cached,
+# so that the user can short-circuit this test for compilers unknown to
+# Autoconf.
+for ac_file in $ac_files ''
+do
+  test -f "$ac_file" || continue
+  case $ac_file in
+    *.$ac_ext | *.xcoff | *.tds | *.d | *.pdb | *.xSYM | *.bb | *.bbg | *.map | *.inf | *.dSYM | *.o | *.obj )
+	;;
+    [ab].out )
+	# We found the default executable, but exeext='' is most
+	# certainly right.
+	break;;
+    *.* )
+	if test ${ac_cv_exeext+y} && test "$ac_cv_exeext" != no;
+	then :; else
+	   ac_cv_exeext=`expr "$ac_file" : '[^.]*\(\..*\)'`
+	fi
+	# We set ac_cv_exeext here because the later test for it is not
+	# safe: cross compilers may not add the suffix if given an `-o'
+	# argument, so we may need to know it at that point already.
+	# Even if this section looks crufty: it has the advantage of
+	# actually working.
+	break;;
+    * )
+	break;;
+  esac
+done
+test "$ac_cv_exeext" = no && ac_cv_exeext=
+
+else $as_nop
+  ac_file=''
+fi
+if test -z "$ac_file"
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: no" >&5
+printf "%s\n" "no" >&6; }
+printf "%s\n" "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+{ { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error 77 "C compiler cannot create executables
+See \`config.log' for more details" "$LINENO" 5; }
+else $as_nop
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+printf "%s\n" "yes" >&6; }
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for C compiler default output file name" >&5
+printf %s "checking for C compiler default output file name... " >&6; }
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_file" >&5
+printf "%s\n" "$ac_file" >&6; }
+ac_exeext=$ac_cv_exeext
+
+rm -f -r a.out a.out.dSYM a.exe conftest$ac_cv_exeext b.out
+ac_clean_files=$ac_clean_files_save
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for suffix of executables" >&5
+printf %s "checking for suffix of executables... " >&6; }
+if { { ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+printf "%s\n" "$ac_try_echo"; } >&5
+  (eval "$ac_link") 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+then :
+  # If both `conftest.exe' and `conftest' are `present' (well, observable)
+# catch `conftest.exe'.  For instance with Cygwin, `ls conftest' will
+# work properly (i.e., refer to `conftest.exe'), while it won't with
+# `rm'.
+for ac_file in conftest.exe conftest conftest.*; do
+  test -f "$ac_file" || continue
+  case $ac_file in
+    *.$ac_ext | *.xcoff | *.tds | *.d | *.pdb | *.xSYM | *.bb | *.bbg | *.map | *.inf | *.dSYM | *.o | *.obj ) ;;
+    *.* ) ac_cv_exeext=`expr "$ac_file" : '[^.]*\(\..*\)'`
+	  break;;
+    * ) break;;
+  esac
+done
+else $as_nop
+  { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "cannot compute suffix of executables: cannot compile and link
+See \`config.log' for more details" "$LINENO" 5; }
+fi
+rm -f conftest conftest$ac_cv_exeext
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_exeext" >&5
+printf "%s\n" "$ac_cv_exeext" >&6; }
+
+rm -f conftest.$ac_ext
+EXEEXT=$ac_cv_exeext
+ac_exeext=$EXEEXT
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <stdio.h>
+int
+main (void)
+{
+FILE *f = fopen ("conftest.out", "w");
+ return ferror (f) || fclose (f) != 0;
+
+  ;
+  return 0;
+}
+_ACEOF
+ac_clean_files="$ac_clean_files conftest.out"
+# Check that the compiler produces executables we can run.  If not, either
+# the compiler is broken, or we cross compile.
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether we are cross compiling" >&5
+printf %s "checking whether we are cross compiling... " >&6; }
+if test "$cross_compiling" != yes; then
+  { { ac_try="$ac_link"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+printf "%s\n" "$ac_try_echo"; } >&5
+  (eval "$ac_link") 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+  if { ac_try='./conftest$ac_cv_exeext'
+  { { case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+printf "%s\n" "$ac_try_echo"; } >&5
+  (eval "$ac_try") 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }; }; then
+    cross_compiling=no
+  else
+    if test "$cross_compiling" = maybe; then
+	cross_compiling=yes
+    else
+	{ { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error 77 "cannot run C compiled programs.
+If you meant to cross compile, use \`--host'.
+See \`config.log' for more details" "$LINENO" 5; }
+    fi
+  fi
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $cross_compiling" >&5
+printf "%s\n" "$cross_compiling" >&6; }
+
+rm -f conftest.$ac_ext conftest$ac_cv_exeext conftest.out
+ac_clean_files=$ac_clean_files_save
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for suffix of object files" >&5
+printf %s "checking for suffix of object files... " >&6; }
+if test ${ac_cv_objext+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.o conftest.obj
+if { { ac_try="$ac_compile"
+case "(($ac_try" in
+  *\"* | *\`* | *\\*) ac_try_echo=\$ac_try;;
+  *) ac_try_echo=$ac_try;;
+esac
+eval ac_try_echo="\"\$as_me:${as_lineno-$LINENO}: $ac_try_echo\""
+printf "%s\n" "$ac_try_echo"; } >&5
+  (eval "$ac_compile") 2>&5
+  ac_status=$?
+  printf "%s\n" "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
+  test $ac_status = 0; }
+then :
+  for ac_file in conftest.o conftest.obj conftest.*; do
+  test -f "$ac_file" || continue;
+  case $ac_file in
+    *.$ac_ext | *.xcoff | *.tds | *.d | *.pdb | *.xSYM | *.bb | *.bbg | *.map | *.inf | *.dSYM ) ;;
+    *) ac_cv_objext=`expr "$ac_file" : '.*\.\(.*\)'`
+       break;;
+  esac
+done
+else $as_nop
+  printf "%s\n" "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+{ { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "cannot compute suffix of object files: cannot compile
+See \`config.log' for more details" "$LINENO" 5; }
+fi
+rm -f conftest.$ac_cv_objext conftest.$ac_ext
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_objext" >&5
+printf "%s\n" "$ac_cv_objext" >&6; }
+OBJEXT=$ac_cv_objext
+ac_objext=$OBJEXT
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether the compiler supports GNU C" >&5
+printf %s "checking whether the compiler supports GNU C... " >&6; }
+if test ${ac_cv_c_compiler_gnu+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+#ifndef __GNUC__
+       choke me
+#endif
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  ac_compiler_gnu=yes
+else $as_nop
+  ac_compiler_gnu=no
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+ac_cv_c_compiler_gnu=$ac_compiler_gnu
+
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_c_compiler_gnu" >&5
+printf "%s\n" "$ac_cv_c_compiler_gnu" >&6; }
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+if test $ac_compiler_gnu = yes; then
+  GCC=yes
+else
+  GCC=
+fi
+ac_test_CFLAGS=${CFLAGS+y}
+ac_save_CFLAGS=$CFLAGS
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking whether $CC accepts -g" >&5
+printf %s "checking whether $CC accepts -g... " >&6; }
+if test ${ac_cv_prog_cc_g+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  ac_save_c_werror_flag=$ac_c_werror_flag
+   ac_c_werror_flag=yes
+   ac_cv_prog_cc_g=no
+   CFLAGS="-g"
+   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  ac_cv_prog_cc_g=yes
+else $as_nop
+  CFLAGS=""
+      cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+
+else $as_nop
+  ac_c_werror_flag=$ac_save_c_werror_flag
+	 CFLAGS="-g"
+	 cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  ac_cv_prog_cc_g=yes
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+   ac_c_werror_flag=$ac_save_c_werror_flag
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cc_g" >&5
+printf "%s\n" "$ac_cv_prog_cc_g" >&6; }
+if test $ac_test_CFLAGS; then
+  CFLAGS=$ac_save_CFLAGS
+elif test $ac_cv_prog_cc_g = yes; then
+  if test "$GCC" = yes; then
+    CFLAGS="-g -O2"
+  else
+    CFLAGS="-g"
+  fi
+else
+  if test "$GCC" = yes; then
+    CFLAGS="-O2"
+  else
+    CFLAGS=
+  fi
+fi
+ac_prog_cc_stdc=no
+if test x$ac_prog_cc_stdc = xno
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $CC option to enable C11 features" >&5
+printf %s "checking for $CC option to enable C11 features... " >&6; }
+if test ${ac_cv_prog_cc_c11+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  ac_cv_prog_cc_c11=no
+ac_save_CC=$CC
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+$ac_c_conftest_c11_program
+_ACEOF
+for ac_arg in '' -std=gnu11
+do
+  CC="$ac_save_CC $ac_arg"
+  if ac_fn_c_try_compile "$LINENO"
+then :
+  ac_cv_prog_cc_c11=$ac_arg
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam
+  test "x$ac_cv_prog_cc_c11" != "xno" && break
+done
+rm -f conftest.$ac_ext
+CC=$ac_save_CC
+fi
+
+if test "x$ac_cv_prog_cc_c11" = xno
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: unsupported" >&5
+printf "%s\n" "unsupported" >&6; }
+else $as_nop
+  if test "x$ac_cv_prog_cc_c11" = x
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: none needed" >&5
+printf "%s\n" "none needed" >&6; }
+else $as_nop
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cc_c11" >&5
+printf "%s\n" "$ac_cv_prog_cc_c11" >&6; }
+     CC="$CC $ac_cv_prog_cc_c11"
+fi
+  ac_cv_prog_cc_stdc=$ac_cv_prog_cc_c11
+  ac_prog_cc_stdc=c11
+fi
+fi
+if test x$ac_prog_cc_stdc = xno
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $CC option to enable C99 features" >&5
+printf %s "checking for $CC option to enable C99 features... " >&6; }
+if test ${ac_cv_prog_cc_c99+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  ac_cv_prog_cc_c99=no
+ac_save_CC=$CC
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+$ac_c_conftest_c99_program
+_ACEOF
+for ac_arg in '' -std=gnu99 -std=c99 -c99 -qlanglvl=extc1x -qlanglvl=extc99 -AC99 -D_STDC_C99=
+do
+  CC="$ac_save_CC $ac_arg"
+  if ac_fn_c_try_compile "$LINENO"
+then :
+  ac_cv_prog_cc_c99=$ac_arg
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam
+  test "x$ac_cv_prog_cc_c99" != "xno" && break
+done
+rm -f conftest.$ac_ext
+CC=$ac_save_CC
+fi
+
+if test "x$ac_cv_prog_cc_c99" = xno
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: unsupported" >&5
+printf "%s\n" "unsupported" >&6; }
+else $as_nop
+  if test "x$ac_cv_prog_cc_c99" = x
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: none needed" >&5
+printf "%s\n" "none needed" >&6; }
+else $as_nop
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cc_c99" >&5
+printf "%s\n" "$ac_cv_prog_cc_c99" >&6; }
+     CC="$CC $ac_cv_prog_cc_c99"
+fi
+  ac_cv_prog_cc_stdc=$ac_cv_prog_cc_c99
+  ac_prog_cc_stdc=c99
+fi
+fi
+if test x$ac_prog_cc_stdc = xno
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $CC option to enable C89 features" >&5
+printf %s "checking for $CC option to enable C89 features... " >&6; }
+if test ${ac_cv_prog_cc_c89+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  ac_cv_prog_cc_c89=no
+ac_save_CC=$CC
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+$ac_c_conftest_c89_program
+_ACEOF
+for ac_arg in '' -qlanglvl=extc89 -qlanglvl=ansi -std -Ae "-Aa -D_HPUX_SOURCE" "-Xc -D__EXTENSIONS__"
+do
+  CC="$ac_save_CC $ac_arg"
+  if ac_fn_c_try_compile "$LINENO"
+then :
+  ac_cv_prog_cc_c89=$ac_arg
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam
+  test "x$ac_cv_prog_cc_c89" != "xno" && break
+done
+rm -f conftest.$ac_ext
+CC=$ac_save_CC
+fi
+
+if test "x$ac_cv_prog_cc_c89" = xno
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: unsupported" >&5
+printf "%s\n" "unsupported" >&6; }
+else $as_nop
+  if test "x$ac_cv_prog_cc_c89" = x
+then :
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: none needed" >&5
+printf "%s\n" "none needed" >&6; }
+else $as_nop
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_prog_cc_c89" >&5
+printf "%s\n" "$ac_cv_prog_cc_c89" >&6; }
+     CC="$CC $ac_cv_prog_cc_c89"
+fi
+  ac_cv_prog_cc_stdc=$ac_cv_prog_cc_c89
+  ac_prog_cc_stdc=c89
+fi
+fi
+
+ac_ext=c
+ac_cpp='$CPP $CPPFLAGS'
+ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
+ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
+ac_compiler_gnu=$ac_cv_c_compiler_gnu
+
+
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: checking for $CC options needed to detect all undeclared functions" >&5
+printf %s "checking for $CC options needed to detect all undeclared functions... " >&6; }
+if test ${ac_cv_c_undeclared_builtin_options+y}
+then :
+  printf %s "(cached) " >&6
+else $as_nop
+  ac_save_CFLAGS=$CFLAGS
+   ac_cv_c_undeclared_builtin_options='cannot detect'
+   for ac_arg in '' -fno-builtin; do
+     CFLAGS="$ac_save_CFLAGS $ac_arg"
+     # This test program should *not* compile successfully.
+     cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+int
+main (void)
+{
+(void) strchr;
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+
+else $as_nop
+  # This test program should compile successfully.
+        # No library function is consistently available on
+        # freestanding implementations, so test against a dummy
+        # declaration.  Include always-available headers on the
+        # off chance that they somehow elicit warnings.
+        cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+#include <float.h>
+#include <limits.h>
+#include <stdarg.h>
+#include <stddef.h>
+extern void ac_decl (int, char *);
+
+int
+main (void)
+{
+(void) ac_decl (0, (char *) 0);
+  (void) ac_decl;
+
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_compile "$LINENO"
+then :
+  if test x"$ac_arg" = x
+then :
+  ac_cv_c_undeclared_builtin_options='none needed'
+else $as_nop
+  ac_cv_c_undeclared_builtin_options=$ac_arg
+fi
+          break
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+fi
+rm -f core conftest.err conftest.$ac_objext conftest.beam conftest.$ac_ext
+    done
+    CFLAGS=$ac_save_CFLAGS
+
+fi
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: result: $ac_cv_c_undeclared_builtin_options" >&5
+printf "%s\n" "$ac_cv_c_undeclared_builtin_options" >&6; }
+  case $ac_cv_c_undeclared_builtin_options in #(
+  'cannot detect') :
+    { { printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
+printf "%s\n" "$as_me: error: in \`$ac_pwd':" >&2;}
+as_fn_error $? "cannot make $CC report undeclared builtins
+See \`config.log' for more details" "$LINENO" 5; } ;; #(
+  'none needed') :
+    ac_c_undeclared_builtin_options='' ;; #(
+  *) :
+    ac_c_undeclared_builtin_options=$ac_cv_c_undeclared_builtin_options ;;
+esac
+
+ac_fn_check_decl "$LINENO" "IN_MASK_CREATE" "ac_cv_have_decl_IN_MASK_CREATE" "#include <sys/inotify.h>
+" "$ac_c_undeclared_builtin_options" "CFLAGS"
+if test "x$ac_cv_have_decl_IN_MASK_CREATE" = xyes
+then :
+  ac_have_decl=1
+else $as_nop
+  ac_have_decl=0
+fi
+printf "%s\n" "#define HAVE_DECL_IN_MASK_CREATE $ac_have_decl" >>confdefs.h
+
+ac_fn_check_decl "$LINENO" "IN_EXCL_UNLINK" "ac_cv_have_decl_IN_EXCL_UNLINK" "#include <sys/inotify.h>
+" "$ac_c_undeclared_builtin_options" "CFLAGS"
+if test "x$ac_cv_have_decl_IN_EXCL_UNLINK" = xyes
+then :
+  ac_have_decl=1
+else $as_nop
+  ac_have_decl=0
+fi
+printf "%s\n" "#define HAVE_DECL_IN_EXCL_UNLINK $ac_have_decl" >>confdefs.h
+
+
+# XXX Do this only for macOS
+ac_fn_check_decl "$LINENO" "kFSEventStreamCreateFlagFileEvents" "ac_cv_have_decl_kFSEventStreamCreateFlagFileEvents" "#include <CoreServices/CoreServices.h>
+" "$ac_c_undeclared_builtin_options" "CFLAGS"
+if test "x$ac_cv_have_decl_kFSEventStreamCreateFlagFileEvents" = xyes
+then :
+  ac_have_decl=1
+else $as_nop
+  ac_have_decl=0
+fi
+printf "%s\n" "#define HAVE_DECL_KFSEVENTSTREAMCREATEFLAGFILEEVENTS $ac_have_decl" >>confdefs.h
+
+ac_fn_check_decl "$LINENO" "kFSEventStreamCreateFlagFullHistory" "ac_cv_have_decl_kFSEventStreamCreateFlagFullHistory" "#include <CoreServices/CoreServices.h>
+" "$ac_c_undeclared_builtin_options" "CFLAGS"
+if test "x$ac_cv_have_decl_kFSEventStreamCreateFlagFullHistory" = xyes
+then :
+  ac_have_decl=1
+else $as_nop
+  ac_have_decl=0
+fi
+printf "%s\n" "#define HAVE_DECL_KFSEVENTSTREAMCREATEFLAGFULLHISTORY $ac_have_decl" >>confdefs.h
+
+ac_fn_check_decl "$LINENO" "kFSEventStreamEventFlagItemCloned" "ac_cv_have_decl_kFSEventStreamEventFlagItemCloned" "#include <CoreServices/CoreServices.h>
+" "$ac_c_undeclared_builtin_options" "CFLAGS"
+if test "x$ac_cv_have_decl_kFSEventStreamEventFlagItemCloned" = xyes
+then :
+  ac_have_decl=1
+else $as_nop
+  ac_have_decl=0
+fi
+printf "%s\n" "#define HAVE_DECL_KFSEVENTSTREAMEVENTFLAGITEMCLONED $ac_have_decl" >>confdefs.h
+
+ac_fn_check_decl "$LINENO" "kFSEventStreamEventFlagItemIsHardlink" "ac_cv_have_decl_kFSEventStreamEventFlagItemIsHardlink" "#include <CoreServices/CoreServices.h>
+" "$ac_c_undeclared_builtin_options" "CFLAGS"
+if test "x$ac_cv_have_decl_kFSEventStreamEventFlagItemIsHardlink" = xyes
+then :
+  ac_have_decl=1
+else $as_nop
+  ac_have_decl=0
+fi
+printf "%s\n" "#define HAVE_DECL_KFSEVENTSTREAMEVENTFLAGITEMISHARDLINK $ac_have_decl" >>confdefs.h
+
+
+# Output
+ac_config_headers="$ac_config_headers src/config.h"
+
+cat >confcache <<\_ACEOF
+# This file is a shell script that caches the results of configure
+# tests run on this system so they can be shared between configure
+# scripts and configure runs, see configure's option --config-cache.
+# It is not useful on other systems.  If it contains results you don't
+# want to keep, you may remove or edit it.
+#
+# config.status only pays attention to the cache file if you give it
+# the --recheck option to rerun configure.
+#
+# `ac_cv_env_foo' variables (set or unset) will be overridden when
+# loading this file, other *unset* `ac_cv_foo' will be assigned the
+# following values.
+
+_ACEOF
+
+# The following way of writing the cache mishandles newlines in values,
+# but we know of no workaround that is simple, portable, and efficient.
+# So, we kill variables containing newlines.
+# Ultrix sh set writes to stderr and can't be redirected directly,
+# and sets the high bit in the cache file unless we assign to the vars.
+(
+  for ac_var in `(set) 2>&1 | sed -n 's/^\([a-zA-Z_][a-zA-Z0-9_]*\)=.*/\1/p'`; do
+    eval ac_val=\$$ac_var
+    case $ac_val in #(
+    *${as_nl}*)
+      case $ac_var in #(
+      *_cv_*) { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: cache variable $ac_var contains a newline" >&5
+printf "%s\n" "$as_me: WARNING: cache variable $ac_var contains a newline" >&2;} ;;
+      esac
+      case $ac_var in #(
+      _ | IFS | as_nl) ;; #(
+      BASH_ARGV | BASH_SOURCE) eval $ac_var= ;; #(
+      *) { eval $ac_var=; unset $ac_var;} ;;
+      esac ;;
+    esac
+  done
+
+  (set) 2>&1 |
+    case $as_nl`(ac_space=' '; set) 2>&1` in #(
+    *${as_nl}ac_space=\ *)
+      # `set' does not quote correctly, so add quotes: double-quote
+      # substitution turns \\\\ into \\, and sed turns \\ into \.
+      sed -n \
+	"s/'/'\\\\''/g;
+	  s/^\\([_$as_cr_alnum]*_cv_[_$as_cr_alnum]*\\)=\\(.*\\)/\\1='\\2'/p"
+      ;; #(
+    *)
+      # `set' quotes correctly as required by POSIX, so do not add quotes.
+      sed -n "/^[_$as_cr_alnum]*_cv_[_$as_cr_alnum]*=/p"
+      ;;
+    esac |
+    sort
+) |
+  sed '
+     /^ac_cv_env_/b end
+     t clear
+     :clear
+     s/^\([^=]*\)=\(.*[{}].*\)$/test ${\1+y} || &/
+     t end
+     s/^\([^=]*\)=\(.*\)$/\1=${\1=\2}/
+     :end' >>confcache
+if diff "$cache_file" confcache >/dev/null 2>&1; then :; else
+  if test -w "$cache_file"; then
+    if test "x$cache_file" != "x/dev/null"; then
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: updating cache $cache_file" >&5
+printf "%s\n" "$as_me: updating cache $cache_file" >&6;}
+      if test ! -f "$cache_file" || test -h "$cache_file"; then
+	cat confcache >"$cache_file"
+      else
+        case $cache_file in #(
+        */* | ?:*)
+	  mv -f confcache "$cache_file"$$ &&
+	  mv -f "$cache_file"$$ "$cache_file" ;; #(
+        *)
+	  mv -f confcache "$cache_file" ;;
+	esac
+      fi
+    fi
+  else
+    { printf "%s\n" "$as_me:${as_lineno-$LINENO}: not updating unwritable cache $cache_file" >&5
+printf "%s\n" "$as_me: not updating unwritable cache $cache_file" >&6;}
+  fi
+fi
+rm -f confcache
+
+test "x$prefix" = xNONE && prefix=$ac_default_prefix
+# Let make expand exec_prefix.
+test "x$exec_prefix" = xNONE && exec_prefix='${prefix}'
+
+DEFS=-DHAVE_CONFIG_H
+
+ac_libobjs=
+ac_ltlibobjs=
+U=
+for ac_i in : $LIBOBJS; do test "x$ac_i" = x: && continue
+  # 1. Remove the extension, and $U if already installed.
+  ac_script='s/\$U\././;s/\.o$//;s/\.obj$//'
+  ac_i=`printf "%s\n" "$ac_i" | sed "$ac_script"`
+  # 2. Prepend LIBOBJDIR.  When used with automake>=1.10 LIBOBJDIR
+  #    will be set to the directory where LIBOBJS objects are built.
+  as_fn_append ac_libobjs " \${LIBOBJDIR}$ac_i\$U.$ac_objext"
+  as_fn_append ac_ltlibobjs " \${LIBOBJDIR}$ac_i"'$U.lo'
+done
+LIBOBJS=$ac_libobjs
+
+LTLIBOBJS=$ac_ltlibobjs
+
+
+
+: "${CONFIG_STATUS=./config.status}"
+ac_write_fail=0
+ac_clean_files_save=$ac_clean_files
+ac_clean_files="$ac_clean_files $CONFIG_STATUS"
+{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: creating $CONFIG_STATUS" >&5
+printf "%s\n" "$as_me: creating $CONFIG_STATUS" >&6;}
+as_write_fail=0
+cat >$CONFIG_STATUS <<_ASEOF || as_write_fail=1
+#! $SHELL
+# Generated by $as_me.
+# Run this file to recreate the current configuration.
+# Compiler output produced by configure, useful for debugging
+# configure, is in config.log if it exists.
+
+debug=false
+ac_cs_recheck=false
+ac_cs_silent=false
+
+SHELL=\${CONFIG_SHELL-$SHELL}
+export SHELL
+_ASEOF
+cat >>$CONFIG_STATUS <<\_ASEOF || as_write_fail=1
+## -------------------- ##
+## M4sh Initialization. ##
+## -------------------- ##
+
+# Be more Bourne compatible
+DUALCASE=1; export DUALCASE # for MKS sh
+as_nop=:
+if test ${ZSH_VERSION+y} && (emulate sh) >/dev/null 2>&1
+then :
+  emulate sh
+  NULLCMD=:
+  # Pre-4.2 versions of Zsh do word splitting on ${1+"$@"}, which
+  # is contrary to our usage.  Disable this feature.
+  alias -g '${1+"$@"}'='"$@"'
+  setopt NO_GLOB_SUBST
+else $as_nop
+  case `(set -o) 2>/dev/null` in #(
+  *posix*) :
+    set -o posix ;; #(
+  *) :
+     ;;
+esac
+fi
+
+
+
+# Reset variables that may have inherited troublesome values from
+# the environment.
+
+# IFS needs to be set, to space, tab, and newline, in precisely that order.
+# (If _AS_PATH_WALK were called with IFS unset, it would have the
+# side effect of setting IFS to empty, thus disabling word splitting.)
+# Quoting is to prevent editors from complaining about space-tab.
+as_nl='
+'
+export as_nl
+IFS=" ""	$as_nl"
+
+PS1='$ '
+PS2='> '
+PS4='+ '
+
+# Ensure predictable behavior from utilities with locale-dependent output.
+LC_ALL=C
+export LC_ALL
+LANGUAGE=C
+export LANGUAGE
+
+# We cannot yet rely on "unset" to work, but we need these variables
+# to be unset--not just set to an empty or harmless value--now, to
+# avoid bugs in old shells (e.g. pre-3.0 UWIN ksh).  This construct
+# also avoids known problems related to "unset" and subshell syntax
+# in other old shells (e.g. bash 2.01 and pdksh 5.2.14).
+for as_var in BASH_ENV ENV MAIL MAILPATH CDPATH
+do eval test \${$as_var+y} \
+  && ( (unset $as_var) || exit 1) >/dev/null 2>&1 && unset $as_var || :
+done
+
+# Ensure that fds 0, 1, and 2 are open.
+if (exec 3>&0) 2>/dev/null; then :; else exec 0</dev/null; fi
+if (exec 3>&1) 2>/dev/null; then :; else exec 1>/dev/null; fi
+if (exec 3>&2)            ; then :; else exec 2>/dev/null; fi
+
+# The user is always right.
+if ${PATH_SEPARATOR+false} :; then
+  PATH_SEPARATOR=:
+  (PATH='/bin;/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 && {
+    (PATH='/bin:/bin'; FPATH=$PATH; sh -c :) >/dev/null 2>&1 ||
+      PATH_SEPARATOR=';'
+  }
+fi
+
+
+# Find who we are.  Look in the path if we contain no directory separator.
+as_myself=
+case $0 in #((
+  *[\\/]* ) as_myself=$0 ;;
+  *) as_save_IFS=$IFS; IFS=$PATH_SEPARATOR
+for as_dir in $PATH
+do
+  IFS=$as_save_IFS
+  case $as_dir in #(((
+    '') as_dir=./ ;;
+    */) ;;
+    *) as_dir=$as_dir/ ;;
+  esac
+    test -r "$as_dir$0" && as_myself=$as_dir$0 && break
+  done
+IFS=$as_save_IFS
+
+     ;;
+esac
+# We did not find ourselves, most probably we were run as `sh COMMAND'
+# in which case we are not to be found in the path.
+if test "x$as_myself" = x; then
+  as_myself=$0
+fi
+if test ! -f "$as_myself"; then
+  printf "%s\n" "$as_myself: error: cannot find myself; rerun with an absolute file name" >&2
+  exit 1
+fi
+
+
+
+# as_fn_error STATUS ERROR [LINENO LOG_FD]
+# ----------------------------------------
+# Output "`basename $0`: error: ERROR" to stderr. If LINENO and LOG_FD are
+# provided, also output the error to LOG_FD, referencing LINENO. Then exit the
+# script with STATUS, using 1 if that was 0.
+as_fn_error ()
+{
+  as_status=$1; test $as_status -eq 0 && as_status=1
+  if test "$4"; then
+    as_lineno=${as_lineno-"$3"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
+    printf "%s\n" "$as_me:${as_lineno-$LINENO}: error: $2" >&$4
+  fi
+  printf "%s\n" "$as_me: error: $2" >&2
+  as_fn_exit $as_status
+} # as_fn_error
+
+
+
+# as_fn_set_status STATUS
+# -----------------------
+# Set $? to STATUS, without forking.
+as_fn_set_status ()
+{
+  return $1
+} # as_fn_set_status
+
+# as_fn_exit STATUS
+# -----------------
+# Exit the shell with STATUS, even in a "trap 0" or "set -e" context.
+as_fn_exit ()
+{
+  set +e
+  as_fn_set_status $1
+  exit $1
+} # as_fn_exit
+
+# as_fn_unset VAR
+# ---------------
+# Portably unset VAR.
+as_fn_unset ()
+{
+  { eval $1=; unset $1;}
+}
+as_unset=as_fn_unset
+
+# as_fn_append VAR VALUE
+# ----------------------
+# Append the text in VALUE to the end of the definition contained in VAR. Take
+# advantage of any shell optimizations that allow amortized linear growth over
+# repeated appends, instead of the typical quadratic growth present in naive
+# implementations.
+if (eval "as_var=1; as_var+=2; test x\$as_var = x12") 2>/dev/null
+then :
+  eval 'as_fn_append ()
+  {
+    eval $1+=\$2
+  }'
+else $as_nop
+  as_fn_append ()
+  {
+    eval $1=\$$1\$2
+  }
+fi # as_fn_append
+
+# as_fn_arith ARG...
+# ------------------
+# Perform arithmetic evaluation on the ARGs, and store the result in the
+# global $as_val. Take advantage of shells that can avoid forks. The arguments
+# must be portable across $(()) and expr.
+if (eval "test \$(( 1 + 1 )) = 2") 2>/dev/null
+then :
+  eval 'as_fn_arith ()
+  {
+    as_val=$(( $* ))
+  }'
+else $as_nop
+  as_fn_arith ()
+  {
+    as_val=`expr "$@" || test $? -eq 1`
+  }
+fi # as_fn_arith
+
+
+if expr a : '\(a\)' >/dev/null 2>&1 &&
+   test "X`expr 00001 : '.*\(...\)'`" = X001; then
+  as_expr=expr
+else
+  as_expr=false
+fi
+
+if (basename -- /) >/dev/null 2>&1 && test "X`basename -- / 2>&1`" = "X/"; then
+  as_basename=basename
+else
+  as_basename=false
+fi
+
+if (as_dir=`dirname -- /` && test "X$as_dir" = X/) >/dev/null 2>&1; then
+  as_dirname=dirname
+else
+  as_dirname=false
+fi
+
+as_me=`$as_basename -- "$0" ||
+$as_expr X/"$0" : '.*/\([^/][^/]*\)/*$' \| \
+	 X"$0" : 'X\(//\)$' \| \
+	 X"$0" : 'X\(/\)' \| . 2>/dev/null ||
+printf "%s\n" X/"$0" |
+    sed '/^.*\/\([^/][^/]*\)\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\/\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\/\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+
+# Avoid depending upon Character Ranges.
+as_cr_letters='abcdefghijklmnopqrstuvwxyz'
+as_cr_LETTERS='ABCDEFGHIJKLMNOPQRSTUVWXYZ'
+as_cr_Letters=$as_cr_letters$as_cr_LETTERS
+as_cr_digits='0123456789'
+as_cr_alnum=$as_cr_Letters$as_cr_digits
+
+
+# Determine whether it's possible to make 'echo' print without a newline.
+# These variables are no longer used directly by Autoconf, but are AC_SUBSTed
+# for compatibility with existing Makefiles.
+ECHO_C= ECHO_N= ECHO_T=
+case `echo -n x` in #(((((
+-n*)
+  case `echo 'xy\c'` in
+  *c*) ECHO_T='	';;	# ECHO_T is single tab character.
+  xy)  ECHO_C='\c';;
+  *)   echo `echo ksh88 bug on AIX 6.1` > /dev/null
+       ECHO_T='	';;
+  esac;;
+*)
+  ECHO_N='-n';;
+esac
+
+# For backward compatibility with old third-party macros, we provide
+# the shell variables $as_echo and $as_echo_n.  New code should use
+# AS_ECHO(["message"]) and AS_ECHO_N(["message"]), respectively.
+as_echo='printf %s\n'
+as_echo_n='printf %s'
+
+rm -f conf$$ conf$$.exe conf$$.file
+if test -d conf$$.dir; then
+  rm -f conf$$.dir/conf$$.file
+else
+  rm -f conf$$.dir
+  mkdir conf$$.dir 2>/dev/null
+fi
+if (echo >conf$$.file) 2>/dev/null; then
+  if ln -s conf$$.file conf$$ 2>/dev/null; then
+    as_ln_s='ln -s'
+    # ... but there are two gotchas:
+    # 1) On MSYS, both `ln -s file dir' and `ln file dir' fail.
+    # 2) DJGPP < 2.04 has no symlinks; `ln -s' creates a wrapper executable.
+    # In both cases, we have to default to `cp -pR'.
+    ln -s conf$$.file conf$$.dir 2>/dev/null && test ! -f conf$$.exe ||
+      as_ln_s='cp -pR'
+  elif ln conf$$.file conf$$ 2>/dev/null; then
+    as_ln_s=ln
+  else
+    as_ln_s='cp -pR'
+  fi
+else
+  as_ln_s='cp -pR'
+fi
+rm -f conf$$ conf$$.exe conf$$.dir/conf$$.file conf$$.file
+rmdir conf$$.dir 2>/dev/null
+
+
+# as_fn_mkdir_p
+# -------------
+# Create "$as_dir" as a directory, including parents if necessary.
+as_fn_mkdir_p ()
+{
+
+  case $as_dir in #(
+  -*) as_dir=./$as_dir;;
+  esac
+  test -d "$as_dir" || eval $as_mkdir_p || {
+    as_dirs=
+    while :; do
+      case $as_dir in #(
+      *\'*) as_qdir=`printf "%s\n" "$as_dir" | sed "s/'/'\\\\\\\\''/g"`;; #'(
+      *) as_qdir=$as_dir;;
+      esac
+      as_dirs="'$as_qdir' $as_dirs"
+      as_dir=`$as_dirname -- "$as_dir" ||
+$as_expr X"$as_dir" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
+	 X"$as_dir" : 'X\(//\)[^/]' \| \
+	 X"$as_dir" : 'X\(//\)$' \| \
+	 X"$as_dir" : 'X\(/\)' \| . 2>/dev/null ||
+printf "%s\n" X"$as_dir" |
+    sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)[^/].*/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+      test -d "$as_dir" && break
+    done
+    test -z "$as_dirs" || eval "mkdir $as_dirs"
+  } || test -d "$as_dir" || as_fn_error $? "cannot create directory $as_dir"
+
+
+} # as_fn_mkdir_p
+if mkdir -p . 2>/dev/null; then
+  as_mkdir_p='mkdir -p "$as_dir"'
+else
+  test -d ./-p && rmdir ./-p
+  as_mkdir_p=false
+fi
+
+
+# as_fn_executable_p FILE
+# -----------------------
+# Test if FILE is an executable regular file.
+as_fn_executable_p ()
+{
+  test -f "$1" && test -x "$1"
+} # as_fn_executable_p
+as_test_x='test -x'
+as_executable_p=as_fn_executable_p
+
+# Sed expression to map a string onto a valid CPP name.
+as_tr_cpp="eval sed 'y%*$as_cr_letters%P$as_cr_LETTERS%;s%[^_$as_cr_alnum]%_%g'"
+
+# Sed expression to map a string onto a valid variable name.
+as_tr_sh="eval sed 'y%*+%pp%;s%[^_$as_cr_alnum]%_%g'"
+
+
+exec 6>&1
+## ----------------------------------- ##
+## Main body of $CONFIG_STATUS script. ##
+## ----------------------------------- ##
+_ASEOF
+test $as_write_fail = 0 && chmod +x $CONFIG_STATUS || ac_write_fail=1
+
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+# Save the log message, to keep $0 and so on meaningful, and to
+# report actual input values of CONFIG_FILES etc. instead of their
+# values after options handling.
+ac_log="
+This file was extended by streamly $as_me 0.11.0, which was
+generated by GNU Autoconf 2.71.  Invocation command line was
+
+  CONFIG_FILES    = $CONFIG_FILES
+  CONFIG_HEADERS  = $CONFIG_HEADERS
+  CONFIG_LINKS    = $CONFIG_LINKS
+  CONFIG_COMMANDS = $CONFIG_COMMANDS
+  $ $0 $@
+
+on `(hostname || uname -n) 2>/dev/null | sed 1q`
+"
+
+_ACEOF
+
+
+case $ac_config_headers in *"
+"*) set x $ac_config_headers; shift; ac_config_headers=$*;;
+esac
+
+
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+# Files that config.status was made for.
+config_headers="$ac_config_headers"
+
+_ACEOF
+
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+ac_cs_usage="\
+\`$as_me' instantiates files and other configuration actions
+from templates according to the current configuration.  Unless the files
+and actions are specified as TAGs, all are instantiated by default.
+
+Usage: $0 [OPTION]... [TAG]...
+
+  -h, --help       print this help, then exit
+  -V, --version    print version number and configuration settings, then exit
+      --config     print configuration, then exit
+  -q, --quiet, --silent
+                   do not print progress messages
+  -d, --debug      don't remove temporary files
+      --recheck    update $as_me by reconfiguring in the same conditions
+      --header=FILE[:TEMPLATE]
+                   instantiate the configuration header FILE
+
+Configuration headers:
+$config_headers
+
+Report bugs to <streamly@composewell.com>.
+streamly home page: <https://streamly.composewell.com>."
+
+_ACEOF
+ac_cs_config=`printf "%s\n" "$ac_configure_args" | sed "$ac_safe_unquote"`
+ac_cs_config_escaped=`printf "%s\n" "$ac_cs_config" | sed "s/^ //; s/'/'\\\\\\\\''/g"`
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+ac_cs_config='$ac_cs_config_escaped'
+ac_cs_version="\\
+streamly config.status 0.11.0
+configured by $0, generated by GNU Autoconf 2.71,
+  with options \\"\$ac_cs_config\\"
+
+Copyright (C) 2021 Free Software Foundation, Inc.
+This config.status script is free software; the Free Software Foundation
+gives unlimited permission to copy, distribute and modify it."
+
+ac_pwd='$ac_pwd'
+srcdir='$srcdir'
+test -n "\$AWK" || AWK=awk
+_ACEOF
+
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+# The default lists apply if the user does not specify any file.
+ac_need_defaults=:
+while test $# != 0
+do
+  case $1 in
+  --*=?*)
+    ac_option=`expr "X$1" : 'X\([^=]*\)='`
+    ac_optarg=`expr "X$1" : 'X[^=]*=\(.*\)'`
+    ac_shift=:
+    ;;
+  --*=)
+    ac_option=`expr "X$1" : 'X\([^=]*\)='`
+    ac_optarg=
+    ac_shift=:
+    ;;
+  *)
+    ac_option=$1
+    ac_optarg=$2
+    ac_shift=shift
+    ;;
+  esac
+
+  case $ac_option in
+  # Handling of the options.
+  -recheck | --recheck | --rechec | --reche | --rech | --rec | --re | --r)
+    ac_cs_recheck=: ;;
+  --version | --versio | --versi | --vers | --ver | --ve | --v | -V )
+    printf "%s\n" "$ac_cs_version"; exit ;;
+  --config | --confi | --conf | --con | --co | --c )
+    printf "%s\n" "$ac_cs_config"; exit ;;
+  --debug | --debu | --deb | --de | --d | -d )
+    debug=: ;;
+  --header | --heade | --head | --hea )
+    $ac_shift
+    case $ac_optarg in
+    *\'*) ac_optarg=`printf "%s\n" "$ac_optarg" | sed "s/'/'\\\\\\\\''/g"` ;;
+    esac
+    as_fn_append CONFIG_HEADERS " '$ac_optarg'"
+    ac_need_defaults=false;;
+  --he | --h)
+    # Conflict between --help and --header
+    as_fn_error $? "ambiguous option: \`$1'
+Try \`$0 --help' for more information.";;
+  --help | --hel | -h )
+    printf "%s\n" "$ac_cs_usage"; exit ;;
+  -q | -quiet | --quiet | --quie | --qui | --qu | --q \
+  | -silent | --silent | --silen | --sile | --sil | --si | --s)
+    ac_cs_silent=: ;;
+
+  # This is an error.
+  -*) as_fn_error $? "unrecognized option: \`$1'
+Try \`$0 --help' for more information." ;;
+
+  *) as_fn_append ac_config_targets " $1"
+     ac_need_defaults=false ;;
+
+  esac
+  shift
+done
+
+ac_configure_extra_args=
+
+if $ac_cs_silent; then
+  exec 6>/dev/null
+  ac_configure_extra_args="$ac_configure_extra_args --silent"
+fi
+
+_ACEOF
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+if \$ac_cs_recheck; then
+  set X $SHELL '$0' $ac_configure_args \$ac_configure_extra_args --no-create --no-recursion
+  shift
+  \printf "%s\n" "running CONFIG_SHELL=$SHELL \$*" >&6
+  CONFIG_SHELL='$SHELL'
+  export CONFIG_SHELL
+  exec "\$@"
+fi
+
+_ACEOF
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+exec 5>>config.log
+{
+  echo
+  sed 'h;s/./-/g;s/^.../## /;s/...$/ ##/;p;x;p;x' <<_ASBOX
+## Running $as_me. ##
+_ASBOX
+  printf "%s\n" "$ac_log"
+} >&5
+
+_ACEOF
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+_ACEOF
+
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+
+# Handling of arguments.
+for ac_config_target in $ac_config_targets
+do
+  case $ac_config_target in
+    "src/config.h") CONFIG_HEADERS="$CONFIG_HEADERS src/config.h" ;;
+
+  *) as_fn_error $? "invalid argument: \`$ac_config_target'" "$LINENO" 5;;
+  esac
+done
+
+
+# If the user did not use the arguments to specify the items to instantiate,
+# then the envvar interface is used.  Set only those that are not.
+# We use the long form for the default assignment because of an extremely
+# bizarre bug on SunOS 4.1.3.
+if $ac_need_defaults; then
+  test ${CONFIG_HEADERS+y} || CONFIG_HEADERS=$config_headers
+fi
+
+# Have a temporary directory for convenience.  Make it in the build tree
+# simply because there is no reason against having it here, and in addition,
+# creating and moving files from /tmp can sometimes cause problems.
+# Hook for its removal unless debugging.
+# Note that there is a small window in which the directory will not be cleaned:
+# after its creation but before its name has been assigned to `$tmp'.
+$debug ||
+{
+  tmp= ac_tmp=
+  trap 'exit_status=$?
+  : "${ac_tmp:=$tmp}"
+  { test ! -d "$ac_tmp" || rm -fr "$ac_tmp"; } && exit $exit_status
+' 0
+  trap 'as_fn_exit 1' 1 2 13 15
+}
+# Create a (secure) tmp directory for tmp files.
+
+{
+  tmp=`(umask 077 && mktemp -d "./confXXXXXX") 2>/dev/null` &&
+  test -d "$tmp"
+}  ||
+{
+  tmp=./conf$$-$RANDOM
+  (umask 077 && mkdir "$tmp")
+} || as_fn_error $? "cannot create a temporary directory in ." "$LINENO" 5
+ac_tmp=$tmp
+
+# Set up the scripts for CONFIG_HEADERS section.
+# No need to generate them if there are no CONFIG_HEADERS.
+# This happens for instance with `./config.status Makefile'.
+if test -n "$CONFIG_HEADERS"; then
+cat >"$ac_tmp/defines.awk" <<\_ACAWK ||
+BEGIN {
+_ACEOF
+
+# Transform confdefs.h into an awk script `defines.awk', embedded as
+# here-document in config.status, that substitutes the proper values into
+# config.h.in to produce config.h.
+
+# Create a delimiter string that does not exist in confdefs.h, to ease
+# handling of long lines.
+ac_delim='%!_!# '
+for ac_last_try in false false :; do
+  ac_tt=`sed -n "/$ac_delim/p" confdefs.h`
+  if test -z "$ac_tt"; then
+    break
+  elif $ac_last_try; then
+    as_fn_error $? "could not make $CONFIG_HEADERS" "$LINENO" 5
+  else
+    ac_delim="$ac_delim!$ac_delim _$ac_delim!! "
+  fi
+done
+
+# For the awk script, D is an array of macro values keyed by name,
+# likewise P contains macro parameters if any.  Preserve backslash
+# newline sequences.
+
+ac_word_re=[_$as_cr_Letters][_$as_cr_alnum]*
+sed -n '
+s/.\{148\}/&'"$ac_delim"'/g
+t rset
+:rset
+s/^[	 ]*#[	 ]*define[	 ][	 ]*/ /
+t def
+d
+:def
+s/\\$//
+t bsnl
+s/["\\]/\\&/g
+s/^ \('"$ac_word_re"'\)\(([^()]*)\)[	 ]*\(.*\)/P["\1"]="\2"\
+D["\1"]=" \3"/p
+s/^ \('"$ac_word_re"'\)[	 ]*\(.*\)/D["\1"]=" \2"/p
+d
+:bsnl
+s/["\\]/\\&/g
+s/^ \('"$ac_word_re"'\)\(([^()]*)\)[	 ]*\(.*\)/P["\1"]="\2"\
+D["\1"]=" \3\\\\\\n"\\/p
+t cont
+s/^ \('"$ac_word_re"'\)[	 ]*\(.*\)/D["\1"]=" \2\\\\\\n"\\/p
+t cont
+d
+:cont
+n
+s/.\{148\}/&'"$ac_delim"'/g
+t clear
+:clear
+s/\\$//
+t bsnlc
+s/["\\]/\\&/g; s/^/"/; s/$/"/p
+d
+:bsnlc
+s/["\\]/\\&/g; s/^/"/; s/$/\\\\\\n"\\/p
+b cont
+' <confdefs.h | sed '
+s/'"$ac_delim"'/"\\\
+"/g' >>$CONFIG_STATUS || ac_write_fail=1
+
+cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
+  for (key in D) D_is_set[key] = 1
+  FS = ""
+}
+/^[\t ]*#[\t ]*(define|undef)[\t ]+$ac_word_re([\t (]|\$)/ {
+  line = \$ 0
+  split(line, arg, " ")
+  if (arg[1] == "#") {
+    defundef = arg[2]
+    mac1 = arg[3]
+  } else {
+    defundef = substr(arg[1], 2)
+    mac1 = arg[2]
+  }
+  split(mac1, mac2, "(") #)
+  macro = mac2[1]
+  prefix = substr(line, 1, index(line, defundef) - 1)
+  if (D_is_set[macro]) {
+    # Preserve the white space surrounding the "#".
+    print prefix "define", macro P[macro] D[macro]
+    next
+  } else {
+    # Replace #undef with comments.  This is necessary, for example,
+    # in the case of _POSIX_SOURCE, which is predefined and required
+    # on some systems where configure will not decide to define it.
+    if (defundef == "undef") {
+      print "/*", prefix defundef, macro, "*/"
+      next
+    }
+  }
+}
+{ print }
+_ACAWK
+_ACEOF
+cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
+  as_fn_error $? "could not setup config headers machinery" "$LINENO" 5
+fi # test -n "$CONFIG_HEADERS"
+
+
+eval set X "    :H $CONFIG_HEADERS    "
+shift
+for ac_tag
+do
+  case $ac_tag in
+  :[FHLC]) ac_mode=$ac_tag; continue;;
+  esac
+  case $ac_mode$ac_tag in
+  :[FHL]*:*);;
+  :L* | :C*:*) as_fn_error $? "invalid tag \`$ac_tag'" "$LINENO" 5;;
+  :[FH]-) ac_tag=-:-;;
+  :[FH]*) ac_tag=$ac_tag:$ac_tag.in;;
+  esac
+  ac_save_IFS=$IFS
+  IFS=:
+  set x $ac_tag
+  IFS=$ac_save_IFS
+  shift
+  ac_file=$1
+  shift
+
+  case $ac_mode in
+  :L) ac_source=$1;;
+  :[FH])
+    ac_file_inputs=
+    for ac_f
+    do
+      case $ac_f in
+      -) ac_f="$ac_tmp/stdin";;
+      *) # Look for the file first in the build tree, then in the source tree
+	 # (if the path is not absolute).  The absolute path cannot be DOS-style,
+	 # because $ac_f cannot contain `:'.
+	 test -f "$ac_f" ||
+	   case $ac_f in
+	   [\\/$]*) false;;
+	   *) test -f "$srcdir/$ac_f" && ac_f="$srcdir/$ac_f";;
+	   esac ||
+	   as_fn_error 1 "cannot find input file: \`$ac_f'" "$LINENO" 5;;
+      esac
+      case $ac_f in *\'*) ac_f=`printf "%s\n" "$ac_f" | sed "s/'/'\\\\\\\\''/g"`;; esac
+      as_fn_append ac_file_inputs " '$ac_f'"
+    done
+
+    # Let's still pretend it is `configure' which instantiates (i.e., don't
+    # use $as_me), people would be surprised to read:
+    #    /* config.h.  Generated by config.status.  */
+    configure_input='Generated from '`
+	  printf "%s\n" "$*" | sed 's|^[^:]*/||;s|:[^:]*/|, |g'
+	`' by configure.'
+    if test x"$ac_file" != x-; then
+      configure_input="$ac_file.  $configure_input"
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: creating $ac_file" >&5
+printf "%s\n" "$as_me: creating $ac_file" >&6;}
+    fi
+    # Neutralize special characters interpreted by sed in replacement strings.
+    case $configure_input in #(
+    *\&* | *\|* | *\\* )
+       ac_sed_conf_input=`printf "%s\n" "$configure_input" |
+       sed 's/[\\\\&|]/\\\\&/g'`;; #(
+    *) ac_sed_conf_input=$configure_input;;
+    esac
+
+    case $ac_tag in
+    *:-:* | *:-) cat >"$ac_tmp/stdin" \
+      || as_fn_error $? "could not create $ac_file" "$LINENO" 5 ;;
+    esac
+    ;;
+  esac
+
+  ac_dir=`$as_dirname -- "$ac_file" ||
+$as_expr X"$ac_file" : 'X\(.*[^/]\)//*[^/][^/]*/*$' \| \
+	 X"$ac_file" : 'X\(//\)[^/]' \| \
+	 X"$ac_file" : 'X\(//\)$' \| \
+	 X"$ac_file" : 'X\(/\)' \| . 2>/dev/null ||
+printf "%s\n" X"$ac_file" |
+    sed '/^X\(.*[^/]\)\/\/*[^/][^/]*\/*$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)[^/].*/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\/\)$/{
+	    s//\1/
+	    q
+	  }
+	  /^X\(\/\).*/{
+	    s//\1/
+	    q
+	  }
+	  s/.*/./; q'`
+  as_dir="$ac_dir"; as_fn_mkdir_p
+  ac_builddir=.
+
+case "$ac_dir" in
+.) ac_dir_suffix= ac_top_builddir_sub=. ac_top_build_prefix= ;;
+*)
+  ac_dir_suffix=/`printf "%s\n" "$ac_dir" | sed 's|^\.[\\/]||'`
+  # A ".." for each directory in $ac_dir_suffix.
+  ac_top_builddir_sub=`printf "%s\n" "$ac_dir_suffix" | sed 's|/[^\\/]*|/..|g;s|/||'`
+  case $ac_top_builddir_sub in
+  "") ac_top_builddir_sub=. ac_top_build_prefix= ;;
+  *)  ac_top_build_prefix=$ac_top_builddir_sub/ ;;
+  esac ;;
+esac
+ac_abs_top_builddir=$ac_pwd
+ac_abs_builddir=$ac_pwd$ac_dir_suffix
+# for backward compatibility:
+ac_top_builddir=$ac_top_build_prefix
+
+case $srcdir in
+  .)  # We are building in place.
+    ac_srcdir=.
+    ac_top_srcdir=$ac_top_builddir_sub
+    ac_abs_top_srcdir=$ac_pwd ;;
+  [\\/]* | ?:[\\/]* )  # Absolute name.
+    ac_srcdir=$srcdir$ac_dir_suffix;
+    ac_top_srcdir=$srcdir
+    ac_abs_top_srcdir=$srcdir ;;
+  *) # Relative name.
+    ac_srcdir=$ac_top_build_prefix$srcdir$ac_dir_suffix
+    ac_top_srcdir=$ac_top_build_prefix$srcdir
+    ac_abs_top_srcdir=$ac_pwd/$srcdir ;;
+esac
+ac_abs_srcdir=$ac_abs_top_srcdir$ac_dir_suffix
+
+
+  case $ac_mode in
+
+  :H)
+  #
+  # CONFIG_HEADER
+  #
+  if test x"$ac_file" != x-; then
+    {
+      printf "%s\n" "/* $configure_input  */" >&1 \
+      && eval '$AWK -f "$ac_tmp/defines.awk"' "$ac_file_inputs"
+    } >"$ac_tmp/config.h" \
+      || as_fn_error $? "could not create $ac_file" "$LINENO" 5
+    if diff "$ac_file" "$ac_tmp/config.h" >/dev/null 2>&1; then
+      { printf "%s\n" "$as_me:${as_lineno-$LINENO}: $ac_file is unchanged" >&5
+printf "%s\n" "$as_me: $ac_file is unchanged" >&6;}
+    else
+      rm -f "$ac_file"
+      mv "$ac_tmp/config.h" "$ac_file" \
+	|| as_fn_error $? "could not create $ac_file" "$LINENO" 5
+    fi
+  else
+    printf "%s\n" "/* $configure_input  */" >&1 \
+      && eval '$AWK -f "$ac_tmp/defines.awk"' "$ac_file_inputs" \
+      || as_fn_error $? "could not create -" "$LINENO" 5
+  fi
+ ;;
+
+
+  esac
+
+done # for ac_tag
+
+
+as_fn_exit 0
+_ACEOF
+ac_clean_files=$ac_clean_files_save
+
+test $ac_write_fail = 0 ||
+  as_fn_error $? "write failure creating $CONFIG_STATUS" "$LINENO" 5
+
+
+# configure is writing to config.log, and then calls config.status.
+# config.status does its own redirection, appending to config.log.
+# Unfortunately, on DOS this fails, as config.log is still kept open
+# by configure, so config.status won't be able to write to it; its
+# output is simply discarded.  So we exec the FD to /dev/null,
+# effectively closing config.log, so it can be properly (re)opened and
+# appended to by config.status.  When coming back to configure, we
+# need to make the FD available again.
+if test "$no_create" != yes; then
+  ac_cs_success=:
+  ac_config_status_args=
+  test "$silent" = yes &&
+    ac_config_status_args="$ac_config_status_args --quiet"
+  exec 5>/dev/null
+  $SHELL $CONFIG_STATUS $ac_config_status_args || ac_cs_success=false
+  exec 5>>config.log
+  # Use ||, not &&, to avoid exiting from the if with $? = 1, which
+  # would make configure fail if this is the last instruction.
+  $ac_cs_success || as_fn_exit 1
+fi
+if test -n "$ac_unrecognized_opts" && test "$enable_option_checking" != no; then
+  { printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: unrecognized options: $ac_unrecognized_opts" >&5
+printf "%s\n" "$as_me: WARNING: unrecognized options: $ac_unrecognized_opts" >&2;}
+fi
+
+
diff --git a/configure.ac b/configure.ac
new file mode 100644
--- /dev/null
+++ b/configure.ac
@@ -0,0 +1,23 @@
+# Input file for autoconf to generate the configure script.
+
+# See https://www.gnu.org/software/autoconf/manual/autoconf.html for help on
+# the macros used in this file.
+
+AC_INIT([streamly], [0.11.0], [streamly@composewell.com], [streamly], [https://streamly.composewell.com])
+
+# To suppress "WARNING: unrecognized options: --with-compiler"
+AC_ARG_WITH([compiler], [GHC])
+
+# XXX Do this only for linux
+AC_CHECK_DECLS([IN_MASK_CREATE],[],[],[#include <sys/inotify.h>])
+AC_CHECK_DECLS([IN_EXCL_UNLINK],[],[],[#include <sys/inotify.h>])
+
+# XXX Do this only for macOS
+AC_CHECK_DECLS([kFSEventStreamCreateFlagFileEvents],[],[],[#include <CoreServices/CoreServices.h>])
+AC_CHECK_DECLS([kFSEventStreamCreateFlagFullHistory],[],[],[#include <CoreServices/CoreServices.h>])
+AC_CHECK_DECLS([kFSEventStreamEventFlagItemCloned],[],[],[#include <CoreServices/CoreServices.h>])
+AC_CHECK_DECLS([kFSEventStreamEventFlagItemIsHardlink],[],[],[#include <CoreServices/CoreServices.h>])
+
+# Output
+AC_CONFIG_HEADERS([src/config.h])
+AC_OUTPUT
diff --git a/src/Streamly/FileSystem/Event.hs b/src/Streamly/FileSystem/Event.hs
new file mode 100644
--- /dev/null
+++ b/src/Streamly/FileSystem/Event.hs
@@ -0,0 +1,45 @@
+-- |
+-- Module      : Streamly.FileSystem.Event
+-- Copyright   : (c) 2020 Composewell Technologies
+-- License     : BSD-3-Clause
+-- Maintainer  : streamly@composewell.com
+-- Stability   : pre-release
+-- Portability : GHC
+--
+-- File system event notification API portable across Linux, macOS and Windows
+-- platforms.
+--
+-- Note that recursive directory tree watch does not work reliably on Linux
+-- (see notes in the Linux module), therefore, recursive watch API is not
+-- provided in this module. However, you can use it from the platform specific
+-- modules.
+--
+-- For platform specific APIs please see the following modules:
+--
+-- * "Streamly.Internal.FS.Event.Darwin"
+-- * "Streamly.Internal.FS.Event.Linux"
+-- * "Streamly.Internal.FS.Event.Windows"
+
+module Streamly.FileSystem.Event
+    (
+    -- * Creating a Watch
+
+      watch
+    -- , watchRecursive
+
+    -- * Handling Events
+    , Event
+    , getAbsPath
+
+    -- ** Item CRUD events
+    , isCreated
+    , isDeleted
+    , isMoved
+    , isModified
+
+    -- ** Exception Conditions
+    , isEventsLost
+    )
+where
+
+import Streamly.Internal.FS.Event
diff --git a/src/Streamly/Internal/FS/Event.hs b/src/Streamly/Internal/FS/Event.hs
new file mode 100644
--- /dev/null
+++ b/src/Streamly/Internal/FS/Event.hs
@@ -0,0 +1,244 @@
+-- |
+-- Module      : Streamly.Internal.FS.Event
+-- Copyright   : (c) 2020 Composewell Technologies
+-- License     : BSD-3-Clause
+-- Maintainer  : streamly@composewell.com
+-- Stability   : pre-release
+-- Portability : GHC
+--
+-- File system event notification API portable across Linux, macOS and Windows
+-- platforms.
+--
+-- Note that recursive directory tree watch does not work reliably on Linux
+-- (see notes in the Linux module), therefore, recursive watch API is not
+-- provided in this module. However, you can use it from the platform specific
+-- modules.
+--
+-- For platform specific APIs please see the following modules:
+--
+-- * "Streamly.Internal.FS.Event.Darwin"
+-- * "Streamly.Internal.FS.Event.Linux"
+-- * "Streamly.Internal.FS.Event.Windows"
+
+-- XXX Need to ensure that the signatures of the exported APIs are same on all
+-- platforms.
+
+module Streamly.Internal.FS.Event
+    (
+    -- * Creating a Watch
+
+      watch
+    -- , watchRecursive
+
+    -- * Handling Events
+    , Event
+    , getAbsPath
+
+    -- ** Item CRUD events
+    , isCreated
+    , isDeleted
+    , isMoved
+    , isModified
+
+    -- ** Exception Conditions
+    , isEventsLost
+
+    -- ** Debugging
+    , showEvent
+    )
+where
+
+import Data.List.NonEmpty (NonEmpty)
+import Streamly.Data.Stream (Stream)
+import Streamly.FileSystem.Path (Path)
+
+#if defined(CABAL_OS_DARWIN)
+import Streamly.Internal.FS.Event.Darwin (Event)
+import qualified Streamly.Internal.FS.Event.Darwin as Event
+#elif defined(CABAL_OS_LINUX)
+import Streamly.Internal.FS.Event.Linux (Event)
+import qualified Streamly.Internal.FS.Event.Linux as Event
+#elif defined(CABAL_OS_WINDOWS)
+import Streamly.Internal.FS.Event.Windows (Event)
+import qualified Streamly.Internal.FS.Event.Windows as Event
+#else
+#error "FS Events not supported on this platform"
+#endif
+
+-- XXX Ensure that defaultConfig is the same for all platforms.
+--
+-- XXX Ensure that equivalent events are generated on all platforms when same
+-- operations are done. Document any differences in behavior on different
+-- platforms. Any events that are not common to all platforms should be
+-- filtered out.
+--
+-- XXX Only need to set common event types for macOS/Linux/Windows
+-- XXX write a test, that generates all types of events that can possibly
+-- occur on each platform. Then create a common test that only checks
+-- for the common subset of those.
+
+-------------------------------------------------------------------------------
+-- Creating a watch
+-------------------------------------------------------------------------------
+
+-- macOS and Windows seem to do a path level watch i.e. they watch the path
+-- rather than the underlying inode, possibly they can map the inode back to a
+-- path?.  On Linux we cannot keep watching a watch root if the inode it is
+-- pointing to has moved. However, the inode continues to be watched in this
+-- case instead of the path, which is not the case for macOS.
+--
+-- To make the behavior same for all platforms, for the Linux case we will have
+-- to stop watching the inode if it moves from under the path
+-- (setUnwatchMoved).  And on macOS we can stop watching  a path if the inode
+-- under it changes i.e. just filter out events for that path.
+--
+-- Also, to make the behavior of Linux same as macOS we need to set
+-- setFollowSymLinks on Linux.
+
+-- XXX Verify all the cases mentioned below using test cases.
+-- XXX Make it fail if the watch root is a file. It works on macOS and Linux
+-- but does not work on Windows.
+
+-- | Start monitoring a list of directories or symbolic links to directories
+-- for file system events.  Monitoring starts from the current time onwards.
+-- The paths are specified as UTF-8 encoded 'Array' of 'Word8'.
+--
+-- If a watch root is a symbolic link then the target of the link is watched.
+-- Fails if the watched path does not exist. If the user does not have
+-- permissions (read and execute?) on the watch root then no events are
+-- generated.  No events are generated if the watch root itself is renamed or
+-- deleted.
+--
+-- This API watches for changes in the watch root directory only, any changes
+-- in the subdirectories of the watch root are not watched. However, on macOS
+-- the watch is always recursive, but do not rely on that behavior, it may
+-- change without notice in future. If you want to use recursive watch please
+-- use platform specific modules.
+--
+-- /Pre-release/
+--
+watch :: NonEmpty Path -> Stream IO Event
+#if defined(CABAL_OS_DARWIN)
+watch = Event.watchRecursive
+#else
+watch = Event.watch
+#endif
+
+-- | Like 'watch' except that if a watched path is a directory the whole
+-- directory tree under it is watched recursively.
+--
+-- On Linux 'watchRecursive' may be more expensive than 'watch'.
+--
+-- /Pre-release/
+--
+_watchRecursive :: NonEmpty Path -> Stream IO Event
+_watchRecursive = Event.watchRecursive
+
+-------------------------------------------------------------------------------
+-- Handling Events
+-------------------------------------------------------------------------------
+
+-- XXX Ensure that on all paltforms the path has same conventions. That is do
+-- not have a trailing path separator on one platfrom and not on another.
+--
+-- XXX We should use getRelPath instead so that the behavior when the root is a
+-- symlink becomes platform independent.
+--
+-- | Get the absolute path of the file system object for which the event is
+-- generated. The path is a UTF-8 encoded array of bytes.
+--
+-- When the watch root is a symlink the behavior is different on different
+-- platforms:
+--
+-- * On Linux and Windows, the absolute path returned is via the original
+-- symlink.
+--
+-- * On macOS the absolute path returned is via the real path of the root after
+-- resolving the symlink.
+--
+-- This API is subject to removal in future, to be replaced by a platform
+-- independent @getRelPath@.
+--
+-- /Pre-release/
+--
+getAbsPath :: Event -> Path
+getAbsPath = Event.getAbsPath
+
+-- | Determine whether the event indicates creation of an object within the
+-- monitored path. This event is generated when any file system object is
+-- created.
+--
+-- For hard links the behavior is different on different operating systems. On
+-- macOS hard linking does not generate a create event, it generates an
+-- 'isInodeAttrsChanged' event on the directory instead (see the Darwin
+-- module). On Linux and Windows hard linking generates a create event.
+--
+-- /Pre-release/
+--
+isCreated :: Event -> Bool
+isCreated = Event.isCreated
+
+-- XXX To make the behavior consistent, can we block the event on watch root on
+-- macOS?
+--
+-- | Determine whether the event indicates deletion of an object within the
+-- monitored path. On Linux and Windows hard link deletion generates a delete
+-- event.
+--
+-- On Linux and Windows, this event does not occur when the watch root itself
+-- is deleted. On macOS it occurs on deleting the watch root when it is not a
+-- symbolic link.
+--
+-- See also 'isRootDeleted' event for Linux.
+--
+-- /Pre-release/
+--
+isDeleted :: Event -> Bool
+isDeleted = Event.isDeleted
+
+-- | Determine whether the event indicates rename of an object within the
+-- monitored path. This event is generated when an object is renamed within the
+-- watched directory or if it is moved out of or in the watched directory.
+-- Moving hard links is no different than other types of objects.
+--
+-- /Pre-release/
+--
+isMoved :: Event -> Bool
+isMoved = Event.isMoved
+
+-- XXX Make the Windows behavior consistent with other platforms by removing
+-- the event from directories.
+--
+-- | Determine whether the event indicates modification of an object within the
+-- monitored path. This event is generated on file modification on all
+-- platforms.
+--
+-- On Linux and macOS this event is never generated for directories.  On
+-- Windows (in recursive watch mode) this event is generated for directories as
+-- well when an object is created in or deleted from the directory.
+--
+-- /Pre-release/
+--
+isModified :: Event -> Bool
+isModified = Event.isModified
+
+-- | An event that indicates that some events before this may have been lost,
+-- therefore, we need to take some recovery action.
+--
+-- /Pre-release/
+--
+isEventsLost :: Event -> Bool
+isEventsLost = Event.isEventsLost
+
+-------------------------------------------------------------------------------
+-- Debugging
+-------------------------------------------------------------------------------
+
+-- | Convert an 'Event' record to a String representation. Note that the output
+-- of this function may be different on different platforms because it may
+-- contain platform specific details.
+--
+-- /Internal/
+--
+showEvent :: Event -> String
+showEvent = Event.showEvent
diff --git a/src/Streamly/Internal/FS/Event/Darwin.c b/src/Streamly/Internal/FS/Event/Darwin.c
new file mode 100644
--- /dev/null
+++ b/src/Streamly/Internal/FS/Event/Darwin.c
@@ -0,0 +1,287 @@
+/*
+ * Code adapted from the Haskell "hfsevents" package.
+ *
+ * Copyright (c) 2012, Luite Stegeman
+ *
+ */
+
+#include <config.h>
+
+#if HAVE_DECL_KFSEVENTSTREAMCREATEFLAGFILEEVENTS
+
+#include <CoreServices/CoreServices.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <FS/Event/Darwin.h>
+
+/*
+ * For reference documentaion see:
+ * https://developer.apple.com/documentation/coreservices/file_system_events?language=objc
+ * https://developer.apple.com/library/archive/documentation/Darwin/Conceptual/FSEvents_ProgGuide/UsingtheFSEventsFramework/UsingtheFSEventsFramework.html
+ *
+ * An OS thread is started which runs the event loop. A pipe is created
+ * and the events are sent to the pipes. The receiver can read the pipe
+ * output end to get the events.
+ */
+
+/******************************************************************************
+ * Create Flags
+ *****************************************************************************/
+
+UInt32 FSEventStreamCreateFlagNoDefer () {
+  return kFSEventStreamCreateFlagNoDefer;
+}
+UInt32 FSEventStreamCreateFlagWatchRoot () {
+  return kFSEventStreamCreateFlagWatchRoot;
+}
+UInt32 FSEventStreamCreateFlagFileEvents () {
+  return kFSEventStreamCreateFlagFileEvents;
+}
+UInt32 FSEventStreamCreateFlagIgnoreSelf () {
+  return kFSEventStreamCreateFlagIgnoreSelf;
+}
+#if 0
+UInt32 FSEventStreamCreateFlagFullHistory = kFSEventStreamCreateFlagFullHistory;
+#endif
+
+/******************************************************************************
+ * Event Flags
+ *****************************************************************************/
+
+UInt32 FSEventStreamEventFlagEventIdsWrapped () {
+  return kFSEventStreamEventFlagEventIdsWrapped;
+}
+UInt32 FSEventStreamEventFlagMustScanSubDirs () {
+  return kFSEventStreamEventFlagMustScanSubDirs;
+}
+UInt32 FSEventStreamEventFlagKernelDropped () {
+  return kFSEventStreamEventFlagKernelDropped;
+}
+UInt32 FSEventStreamEventFlagUserDropped () {
+  return kFSEventStreamEventFlagUserDropped;
+}
+UInt32 FSEventStreamEventFlagHistoryDone () {
+  return kFSEventStreamEventFlagHistoryDone;
+}
+UInt32 FSEventStreamEventFlagRootChanged () {
+  return kFSEventStreamEventFlagRootChanged;
+}
+UInt32 FSEventStreamEventFlagMount () {
+  return kFSEventStreamEventFlagMount;
+}
+UInt32 FSEventStreamEventFlagUnmount () {
+  return kFSEventStreamEventFlagUnmount;
+}
+UInt32 FSEventStreamEventFlagItemChangeOwner () {
+  return kFSEventStreamEventFlagItemChangeOwner;
+}
+UInt32 FSEventStreamEventFlagItemInodeMetaMod () {
+  return kFSEventStreamEventFlagItemInodeMetaMod;
+}
+UInt32 FSEventStreamEventFlagItemFinderInfoMod () {
+  return kFSEventStreamEventFlagItemFinderInfoMod;
+}
+UInt32 FSEventStreamEventFlagItemXattrMod () {
+  return kFSEventStreamEventFlagItemXattrMod;
+}
+UInt32 FSEventStreamEventFlagItemCreated () {
+  return kFSEventStreamEventFlagItemCreated;
+}
+UInt32 FSEventStreamEventFlagItemRemoved () {
+  return kFSEventStreamEventFlagItemRemoved;
+}
+UInt32 FSEventStreamEventFlagItemRenamed () {
+  return kFSEventStreamEventFlagItemRenamed;
+}
+UInt32 FSEventStreamEventFlagItemModified () {
+  return kFSEventStreamEventFlagItemModified;
+}
+#if __MAC_OS_X_VERSION_MIN_REQUIRED >= 101300
+UInt32 FSEventStreamEventFlagItemCloned () {
+  return kFSEventStreamEventFlagItemCloned;
+}
+#endif
+UInt32 FSEventStreamEventFlagItemIsDir () {
+  return kFSEventStreamEventFlagItemIsDir;
+}
+UInt32 FSEventStreamEventFlagItemIsFile () {
+  return kFSEventStreamEventFlagItemIsFile;
+}
+UInt32 FSEventStreamEventFlagItemIsSymlink () {
+  return kFSEventStreamEventFlagItemIsSymlink;
+}
+#if __MAC_OS_X_VERSION_MIN_REQUIRED >= 101000
+UInt32 FSEventStreamEventFlagItemIsHardlink () {
+  return kFSEventStreamEventFlagItemIsHardlink;
+}
+#endif
+UInt32 FSEventStreamEventFlagItemIsLastHardlink () {
+  return kFSEventStreamEventFlagItemIsLastHardlink;
+}
+
+/******************************************************************************
+ * Event watch
+ *****************************************************************************/
+
+/* Write an event to the pipe input fd */
+static void writeEvent(int fd, UInt64 eventId, UInt64 eventFlags, char* path)
+{
+    UInt64 buf[3];
+    /* XXX Is the path string in UTF-8? */
+    size_t len = strlen(path);
+
+    buf[0] = eventId;
+    buf[1] = eventFlags;
+    buf[2] = (UInt64)len;
+    write(fd, buf, 3 * sizeof(UInt64));
+    write(fd, path, len);
+}
+
+struct watch
+{
+    FSEventStreamRef eventStream;
+    dispatch_queue_t queue;
+    int writefd;
+};
+
+/* Just writes the event to the pipe input fd */
+static void watchCallback
+    ( ConstFSEventStreamRef streamRef
+    , void *clientCallBackInfo
+    , size_t n
+    , void *eventPaths
+    , const FSEventStreamEventFlags eventFlags[]
+    , const FSEventStreamEventId eventIds[]
+    )
+{
+    int i;
+    struct watch *w = clientCallBackInfo;
+    char **paths = eventPaths;
+
+    for (i = 0; i < n; i++) {
+        writeEvent(w->writefd, eventIds[i], eventFlags[i], paths[i]);
+    }
+}
+
+#define MAX_WATCH_PATHS 4096
+
+static void free_cffolders(CFStringRef *cffolders, int n) {
+    int i;
+    for (i = 0; i < n; i++) {
+        CFRelease (cffolders[i]);
+    }
+    free(cffolders);
+}
+
+int createWatch
+    ( struct pathName* folders
+    , int n  /* number of entries in folders */
+    , UInt32 createFlags
+    , UInt64 since
+    , double latency
+    , int* fd
+    , void** wp
+    )
+{
+    if (n > MAX_WATCH_PATHS) {
+      return -1;
+    }
+
+    int pfds[2];
+    if (pipe (pfds)) {
+      return -1;
+    }
+
+    /*
+     * XXX We can possibly use since == 0 to get all events since
+     * beginning of time
+     */
+    if (!since) {
+      since = kFSEventStreamEventIdSinceNow;
+    }
+
+    struct watch *w = malloc(sizeof(struct watch));
+    if (!w) {
+      goto cleanup_pipe;
+    }
+
+    /* Setup paths array */
+    CFStringRef *cffolders = malloc(n * sizeof(CFStringRef));
+    if (!cffolders) {
+      goto cleanup_watch;
+    }
+
+    /* Create event stream using paths and context*/
+    int i;
+    for(i = 0; i < n; i++) {
+      cffolders[i] = CFStringCreateWithBytes
+          ( NULL
+          , folders[i].pathBytes
+          , folders[i].pathLen
+          , kCFStringEncodingUTF8
+          , false
+          );
+      if (!cffolders[i]) {
+          free_cffolders(cffolders, i);
+          goto cleanup_watch;
+      }
+    }
+    CFArrayRef paths = CFArrayCreate(NULL, (const void **)cffolders, n, NULL);
+    if (!paths) {
+      free_cffolders(cffolders, n);
+      goto cleanup_watch;
+    }
+
+    FSEventStreamContext ctx;
+    ctx.version = 0;
+    ctx.info = (void*)w;
+    ctx.retain = NULL;
+    ctx.release = NULL;
+    ctx.copyDescription = NULL;
+
+    w->eventStream = FSEventStreamCreate
+        (NULL, &watchCallback, &ctx, paths, since, latency, createFlags);
+    free_cffolders(cffolders, n);
+    CFRelease(paths);
+
+    if(w->eventStream == NULL) {
+      goto cleanup_watch;
+    }
+
+    w->queue = dispatch_queue_create("com.composewell.streamly", NULL);
+    if (!w->queue) {
+      goto cleanup_es;
+    }
+
+    w->writefd = pfds[1];
+    *fd = pfds[0];
+    *wp = w;
+    FSEventStreamSetDispatchQueue(w->eventStream, w->queue);
+    FSEventStreamStart(w->eventStream);
+    return 0;
+
+cleanup_es:
+    FSEventStreamRelease(w->eventStream);
+cleanup_watch:
+    free(w);
+cleanup_pipe:
+    close(pfds[0]);
+    close(pfds[1]);
+    return -1;
+}
+
+/******************************************************************************
+ * Stop a watch event loop
+ *****************************************************************************/
+
+void destroyWatch(struct watch* w) {
+    /* Stop and invalidate the event stream */
+    FSEventStreamFlushSync(w->eventStream);
+    FSEventStreamStop(w->eventStream);
+    FSEventStreamInvalidate(w->eventStream);
+    dispatch_release(w->queue);
+    FSEventStreamRelease(w->eventStream);
+    close(w->writefd);
+    free(w);
+}
+#endif
diff --git a/src/Streamly/Internal/FS/Event/Darwin.h b/src/Streamly/Internal/FS/Event/Darwin.h
new file mode 100644
--- /dev/null
+++ b/src/Streamly/Internal/FS/Event/Darwin.h
@@ -0,0 +1,63 @@
+#include <config.h>
+
+struct watch;
+
+struct pathName {
+    const UInt8 *pathBytes;
+    size_t pathLen;
+};
+
+int createWatch
+    ( struct pathName* folders
+    , int n  /* number of entries in "folders" */
+    , UInt32 createFlags
+    , UInt64 since
+    , double latency
+    , int* fd
+    , void** wp
+    );
+
+void destroyWatch(struct watch* w);
+
+/******************************************************************************
+ * Create Flags
+ *****************************************************************************/
+
+UInt32 FSEventStreamCreateFlagNoDefer ();
+UInt32 FSEventStreamCreateFlagWatchRoot ();
+UInt32 FSEventStreamCreateFlagFileEvents ();
+UInt32 FSEventStreamCreateFlagIgnoreSelf ();
+#if HAVE_DECL_KFSEVENTSTREAMCREATEFLAGFULLHISTORY
+UInt32 FSEventStreamCreateFlagFullHistory;
+#endif
+
+/******************************************************************************
+ * Event Flags
+ *****************************************************************************/
+
+UInt32 FSEventStreamEventFlagEventIdsWrapped ();
+UInt32 FSEventStreamEventFlagMustScanSubDirs ();
+UInt32 FSEventStreamEventFlagKernelDropped ();
+UInt32 FSEventStreamEventFlagUserDropped ();
+UInt32 FSEventStreamEventFlagHistoryDone ();
+UInt32 FSEventStreamEventFlagRootChanged ();
+UInt32 FSEventStreamEventFlagMount ();
+UInt32 FSEventStreamEventFlagUnmount ();
+UInt32 FSEventStreamEventFlagItemChangeOwner ();
+UInt32 FSEventStreamEventFlagItemInodeMetaMod ();
+UInt32 FSEventStreamEventFlagItemFinderInfoMod ();
+UInt32 FSEventStreamEventFlagItemXattrMod ();
+UInt32 FSEventStreamEventFlagItemCreated ();
+UInt32 FSEventStreamEventFlagItemRemoved ();
+UInt32 FSEventStreamEventFlagItemRenamed ();
+UInt32 FSEventStreamEventFlagItemModified ();
+#if HAVE_DECL_KFSEVENTSTREAMEVENTFLAGITEMCLONED
+UInt32 FSEventStreamEventFlagItemCloned ();
+#endif
+UInt32 FSEventStreamEventFlagItemIsDir ();
+UInt32 FSEventStreamEventFlagItemIsFile ();
+UInt32 FSEventStreamEventFlagItemIsSymlink ();
+#if HAVE_DECL_KFSEVENTSTREAMEVENTFLAGITEMISHARDLINK
+UInt32 FSEventStreamEventFlagItemIsHardlink ();
+#endif
+UInt32 FSEventStreamEventFlagItemIsLastHardlink ();
diff --git a/src/Streamly/Internal/FS/Event/Darwin.hs b/src/Streamly/Internal/FS/Event/Darwin.hs
new file mode 100644
--- /dev/null
+++ b/src/Streamly/Internal/FS/Event/Darwin.hs
@@ -0,0 +1,1111 @@
+-- |
+-- Module      : Streamly.Internal.FS.Event.Darwin
+-- Copyright   : (c) 2020 Composewell Technologies
+-- License     : BSD-3-Clause
+-- Maintainer  : streamly@composewell.com
+-- Stability   : pre-release
+-- Portability : GHC
+--
+-- =Overview
+--
+-- Use 'watchRecursive' with a list of file system paths you want to watch as
+-- argument. It returns a stream of 'Event' representing the file system events
+-- occurring under the watched paths.
+--
+-- @
+-- {-\# LANGUAGE MagicHash #-}
+-- Stream.mapM_ (putStrLn . 'showEvent') $ 'watchRecursive' [Path.fromString "path"]
+-- @
+--
+-- 'Event' is an opaque type. Accessor functions (e.g. 'showEvent' above)
+-- provided in this module are used to determine the attributes of the event.
+--
+-- =Design notes
+--
+-- For reference documentation see:
+--
+-- * "<https://developer.apple.com/library/archive/documentation/Darwin/Conceptual/FSEvents_ProgGuide/UsingtheFSEventsFramework/UsingtheFSEventsFramework.html Apple FS Events Programming Guide>"
+-- * "<https://developer.apple.com/documentation/coreservices/file_system_events?language=objc Apple FS Events Reference>"
+--
+-- We try to keep the macOS\/Linux/Windows event handling APIs and defaults
+-- semantically and syntactically as close as possible.
+--
+-- =BUGS
+--
+-- XXX Check the behavior for Windows/Linux where applicable. Mention these in
+-- the common module so that users are aware of the portability issues.
+--
+-- There may be some idiosyncrasies in event reporting.
+--
+-- 1. Multiple events may be coalesced into a single event having multiple
+-- flags set.  For example, on macOS 10.15.6, "touch x; rm x" or "touch x; mv x
+-- y" produces an event with both "Created" and "Deleted/Moved" flags set.
+--
+-- 2. The same event can occur multiple times. For example, "touch x; sleep 1;
+-- rm x" generates a "Created" event followed by an event with both "Created"
+-- and "Deleted" flags set. Similarly, a cloned event can also occur multiple
+-- times.
+--
+-- 3. Some events can go missing and only the latest one is reported. See
+-- 'isCreated' for one such case.
+--
+-- XXX write a test case for this, and check on all platforms.
+--
+-- 4. When @rm -rf@ is used on the watched root directory, only one 'isDeleted'
+-- event occurs and that is for the root. However, @rm -rf@ on a directory
+-- inside the watch root produces 'isDeleted' events for all files.
+--
+-- XXX write a test case for this, and check on all platforms.
+--
+-- 5. When a file is moved, a move event occurs for both the source and the
+-- destination files. There seems to be no way to distinguish the source and
+-- the destination. Perhaps the lower eventId can be considered as source.
+--
+-- XXX cloned event is specific to macOS.  Translate it to the same events as
+-- on copying.
+--
+-- 6. When a file is cloned both source and destination generate a cloned
+-- event, however the source has lower eventId and destination may have
+-- OwnerGroupModeChanged, InodeAttrsChanged, Created flags as well.
+--
+-- You may have to stat the path of the event to know more information about
+-- what might have happened.  It may be a good idea to watch the behavior of
+-- events you are handling before you can rely on it. See the individual event
+-- APIs for some of the known issues marked with `BUGS`. Also see the "Handling
+-- Events" section in the "Apple FS Events Programming Guide".
+--
+-- * "<https://stackoverflow.com/questions/18415285/osx-fseventstreameventflags-not-working-correctly Stack overflow question on event coalescing>"
+--
+-- =TODO
+--
+-- APIs for persistent event-id related functionality, to get events from
+-- specific event-id etc are not implemented.
+
+#include <config.h>
+
+-- macOS 10.7+
+#if HAVE_DECL_KFSEVENTSTREAMCREATEFLAGFILEEVENTS
+
+module Streamly.Internal.FS.Event.Darwin
+    (
+    -- * Creating a Watch
+
+    -- ** Default configuration
+      Config (..)
+    , defaultConfig
+
+    -- ** Watch Behavior
+    , BatchInfo (..)
+    , setEventBatching
+
+    -- ** Events of Interest
+    , setRootPathEvents
+    , setFileEvents
+    , setIgnoreSelf
+#if HAVE_DECL_KFSEVENTSTREAMCREATEFLAGFULLHISTORY
+    , setFullHistory
+#endif
+    , setAllEvents
+
+    -- ** Watch APIs
+    , watch
+    , watchRecursive
+    , watchWith
+
+    -- * Handling Events
+    , Event
+    , getEventId
+    , getAbsPath
+
+    -- ** Root Level Events
+    -- | Events that belong to the root path as a whole and not to specific
+    -- items contained in it.
+    , isMounted
+    , isUnmounted
+    , isHistoryDone
+    , isRootPathEvent
+
+    -- ** Item Level Metadata change
+    , isAttrsModified
+    , isSecurityModified
+    , isXAttrsModified
+    , isFinderInfoModified
+
+    -- ** Item Level CRUD events
+    , isCreated
+    , isDeleted
+    , isMoved
+    , isModified
+#if HAVE_DECL_KFSEVENTSTREAMEVENTFLAGITEMCLONED
+    , isCloned
+#endif
+
+    -- ** Item Path info
+    , isDir
+    , isFile
+    , isSymLink
+#if HAVE_DECL_KFSEVENTSTREAMEVENTFLAGITEMISHARDLINK
+    , isHardLink
+    , isLastHardLink
+#endif
+
+    -- ** Exception Conditions
+    , isEventIdWrapped
+    , isEventsLost
+    , isKernelDropped
+    , isUserDropped
+
+    -- * Debugging
+    , showEvent
+    )
+where
+
+import Control.Concurrent (MVar, newMVar, takeMVar, putMVar)
+import Control.Monad (when)
+import Control.Monad.Cont (runCont, cont)
+import Data.Bits ((.|.), (.&.), complement)
+import Data.List.NonEmpty (NonEmpty)
+import Data.Word (Word8, Word32, Word64)
+import Foreign.C.Types (CInt(..), CDouble(..), CSize(..), CUChar(..))
+import Foreign.Marshal.Alloc (alloca)
+import Foreign.Marshal.Array (withArray)
+import Foreign.Ptr (Ptr, castPtr)
+import Foreign.Storable (Storable(..))
+import GHC.IO.Handle.FD (fdToHandle)
+import Streamly.Internal.Data.Stream (Stream)
+import Streamly.Internal.Data.Parser (Parser)
+import Streamly.Internal.Data.Array (Array(..))
+import Streamly.Internal.FileSystem.Path (Path)
+import System.IO (Handle, hClose)
+
+import qualified Data.List.NonEmpty as NonEmpty
+import qualified Streamly.Internal.Data.Parser as PR
+import qualified Streamly.Internal.Data.Stream as S
+import qualified Streamly.Internal.FileSystem.Handle as FH
+import qualified Streamly.Internal.Data.Array as A
+import qualified Streamly.Internal.FileSystem.Path as Path
+
+-------------------------------------------------------------------------------
+-- Utils
+-------------------------------------------------------------------------------
+
+-- NOTE: "contListMap" is part of the unexposed module:
+-- Streamly.Internal.Data.Cont
+
+-- | Given a continuation based transformation from @a@ to @b@ and a
+-- continuation based transformation from @[b]@ to @c@, make continuation based
+-- transformation from @[a]@ to @c@.
+--
+-- /Pre-release/
+
+-- You can read the definition as:
+--
+-- > contListMap f g = \xs final ->
+--
+contListMap ::
+       (a -> (b -> r) -> r)      -- transform a -> b
+    -> ([b] -> (c -> r) -> r)    -- transform [b] -> c
+    -> ([a] -> (c -> r) -> r)    -- transform [a] -> c
+contListMap f g xs final =
+    let bconts = fmap (cont . f) xs  -- [Cont b]
+        blistCont = sequence bconts  -- Cont [b]
+        k ys = g ys final            -- [b] -> r
+     in runCont blistCont k          -- r
+
+-------------------------------------------------------------------------------
+-- Subscription to events
+-------------------------------------------------------------------------------
+
+-- XXX Add a recursive option to Config
+-- Keep setRecursiveMode False as undefined for now until we implement it.
+--
+-- | Watch configuration, used to specify the events of interest and the
+-- behavior of the watch.
+--
+-- /Pre-release/
+--
+data Config = Config
+    { latency :: Double
+    , createFlags   :: Word32
+    }
+
+-------------------------------------------------------------------------------
+-- Batching Events
+-------------------------------------------------------------------------------
+
+foreign import ccall safe
+    "FS/Event/Darwin.h FSEventStreamCreateFlagNoDefer"
+    kFSEventStreamCreateFlagNoDefer :: Word32
+
+-- | Determines how multiple events are batched or throttled.
+data BatchInfo =
+      Throttle Double -- ^ Deliver an event immediately but suppress the
+                      -- following events upto the specified time.
+    | Batch Double    -- ^ Collapse all events that occurred in the specified
+                      -- time window (in seconds) and deliver them as a single
+                      -- batch.
+
+-- | Set how the events should be batched. See 'BatchInfo' for details.  A
+-- negative value for time is treated as 0.
+--
+-- /default: Batch 0.0/
+--
+-- /macOS 10.5+/
+--
+-- /Pre-release/
+--
+setEventBatching :: BatchInfo -> Config -> Config
+setEventBatching batchInfo cfg =
+    let (t, status) =
+            case batchInfo of
+                Throttle sec | sec < 0 -> (0, True)
+                Throttle sec -> (sec, True)
+                Batch sec | sec < 0 -> (0, False)
+                Batch sec -> (sec, False)
+    in setFlag kFSEventStreamCreateFlagNoDefer status $ cfg {latency = t}
+
+-------------------------------------------------------------------------------
+-- Boolean settings
+-------------------------------------------------------------------------------
+
+setFlag :: Word32 -> Bool -> Config -> Config
+setFlag mask status cfg@Config{..} =
+    let flags =
+            if status
+            then createFlags .|. mask
+            else createFlags .&. complement mask
+    in cfg {createFlags = flags}
+
+foreign import ccall safe
+    "FSEventStreamCreateFlagWatchRoot"
+    kFSEventStreamCreateFlagWatchRoot :: Word32
+
+-- XXX write a test case for this, and check on all platforms. The behavior on
+-- macOS is slightly different as a create event is also generated.
+--
+-- | Any changes to the path (delete, rename, or create) of an object are
+-- reported as events for its parent directory. Such events are not reported
+-- for the watch root itself because its parent is not being watched. When
+-- 'setRootPathEvents' is 'True', an 'isRootPathEvent' event is generated with an
+-- eventId 0 if the watch root is deleted, renamed or created.
+--
+-- Note: We have observed that an 'isDeleted' event occurs for the root path
+-- (when it is a regular dir and not symlink) even when this option is off.
+--
+-- /default: False/
+--
+-- /macOS 10.5+/
+--
+-- /Pre-release/
+--
+setRootPathEvents :: Bool -> Config -> Config
+setRootPathEvents = setFlag kFSEventStreamCreateFlagWatchRoot
+
+foreign import ccall safe
+    "FSEventStreamCreateFlagFileEvents"
+    kFSEventStreamCreateFlagFileEvents :: Word32
+
+-- | When this is 'False' only events for the watched directories are reported.
+-- For example, when a file is created inside a directory it is reported as an
+-- event, the path name in the event is the path of the directory being watched
+-- and not of the specific item for which the event occurred.  Events cannot be
+-- distinguished based on the type of event.  For example, we cannot determine
+-- if an event is a "create" or "delete", we only know that some event ocurred
+-- under the watched directory hierarchy.
+--
+-- When it is 'True' the path reported in the event is the path of the item and
+-- not the of the directory in which it is contained. We can use the event
+-- accessor functions to determine the event type and the path type etc.
+--
+-- /default: True/
+--
+-- /macOS 10.7+/
+--
+-- /Pre-release/
+--
+setFileEvents :: Bool -> Config -> Config
+setFileEvents = setFlag kFSEventStreamCreateFlagFileEvents
+
+foreign import ccall safe
+    "FSEventStreamCreateFlagIgnoreSelf"
+    kFSEventStreamCreateFlagIgnoreSelf :: Word32
+
+-- | When this is 'True' events generated by the current process are not
+-- reported.
+--
+-- /default: False/
+--
+-- /macOS 10.6+/
+--
+-- /Pre-release/
+--
+setIgnoreSelf :: Bool -> Config -> Config
+setIgnoreSelf = setFlag kFSEventStreamCreateFlagIgnoreSelf
+
+#if HAVE_DECL_KFSEVENTSTREAMCREATEFLAGFULLHISTORY
+foreign import ccall safe
+    "FSEventStreamCreateFlagFullHistory"
+    kFSEventStreamCreateFlagFullHistory :: Word32
+
+-- | When this is 'True' all events since the beginning of time are reported.
+--
+-- /default: False/
+--
+-- /macOS 10.15+/
+--
+-- /Pre-release/
+--
+setFullHistory :: Bool -> Config -> Config
+setFullHistory = setFlag kFSEventStreamCreateFlagFullHistory
+#endif
+
+-- | Set all tunable events 'True' or 'False'. Equivalent to setting:
+--
+-- * setRootPathEvents
+-- * setFileEvents
+--
+-- /Pre-release/
+--
+setAllEvents :: Bool -> Config -> Config
+setAllEvents s =
+      setRootPathEvents s
+    . setFileEvents s
+
+-------------------------------------------------------------------------------
+-- Default config
+-------------------------------------------------------------------------------
+
+-- | The default settings are:
+--
+-- * 'setEventBatching' ('Batch' 0.0)
+-- * 'setFileEvents' 'True'
+-- * 'setRootPathEvents' 'False'
+-- * 'setIgnoreSelf' 'False'
+#if HAVE_DECL_KFSEVENTSTREAMCREATEFLAGFULLHISTORY
+-- * 'setFullHistory' 'False'
+#endif
+--
+-- /Pre-release/
+--
+defaultConfig :: Config
+defaultConfig = setFileEvents True $ Config
+    { latency = 0.0
+    , createFlags = 0
+    }
+
+-------------------------------------------------------------------------------
+-- Open an event stream (C FFI)
+-------------------------------------------------------------------------------
+
+-- See FS/Event/Darwin.h
+
+data CWatch
+
+-- Representation of "struct pathName" in "FS/Event/Darwin.h"
+data PathName = PathName
+    { pathBytes :: Ptr CUChar
+    , pathLen :: CSize
+    }
+
+instance Storable PathName where
+    alignment _ = sizeOf (undefined :: Ptr a)
+    sizeOf _ = sizeOf (undefined :: Ptr CUChar) + sizeOf (undefined :: CSize)
+    peek ptr = do
+        bptr <- peekByteOff ptr 0
+        len <- peekByteOff ptr (sizeOf (undefined :: Ptr CUChar))
+        return $ PathName bptr len
+    poke ptr PathName{..} = do
+        pokeByteOff ptr 0 pathBytes
+        pokeByteOff ptr (sizeOf (undefined :: Ptr CUChar)) pathLen
+
+foreign import ccall safe "FS/Event/Darwin.h createWatch" createWatch
+    :: Ptr PathName
+    -> CInt
+    -> Word32
+    -> Word64
+    -> CDouble
+    -> Ptr CInt
+    -> Ptr (Ptr CWatch)
+    -> IO CInt
+
+foreign import ccall safe "FS/Event/Darwin.h destroyWatch" destroyWatch
+    :: Ptr CWatch -> IO ()
+
+-------------------------------------------------------------------------------
+-- Open an event stream
+-------------------------------------------------------------------------------
+
+-- | A handle for a watch.
+data Watch = Watch Handle (Ptr CWatch) (MVar Bool)
+
+-- | Given a 'Config' and @paths@ start monitoring the paths for file system
+-- events. Returns a 'Watch' handle which can then be used to read the event
+-- stream or to close the watch.
+--
+-- Implementation Note: This API creates an OS level thread where an event loop
+-- runs and writes the events to the write side fd of a POSIX pipe. Event
+-- stream APIs read the events from the read end of this pipe.  Since an OS
+-- level thread is forked, creating a new watch stream is expensive. It is
+-- advised to minimize the number of watches.
+--
+-- /Pre-release/
+--
+openWatch :: Config -> NonEmpty Path -> IO Watch
+openWatch Config{..} paths = do
+    -- XXX write a test case when path does not exist
+    -- XXX write a test case when there are no permissions
+    -- XXX check whether the path exists. If the path does not exist and
+    -- is created later it cannot be properly monitored. Also a user may
+    -- inadvertently provide a path for which the user may not have permission
+    -- and then later wonder why events are not being reported.
+    withPathNames (NonEmpty.toList paths) $ \arraysPtr ->
+        alloca $ \fdPtr -> do
+        alloca $ \watchPPtr -> do
+            let nArrays = fromIntegral (NonEmpty.length paths)
+                seconds = realToFrac latency
+            r <- createWatch
+                    arraysPtr nArrays createFlags 0 seconds fdPtr watchPPtr
+            when (r /= 0) $
+                ioError (userError "openWatch: failed to create watch.")
+            fd <- peek fdPtr
+            h <- fdToHandle fd
+            watchPtr <- peek watchPPtr
+            closeLock <- newMVar False
+            return $ Watch h watchPtr closeLock
+
+    where
+
+    withPathName :: Path -> (PathName -> IO a) -> IO a
+    withPathName path act = do
+        A.unsafePinnedAsPtr (Path.toArray path) $ \ptr byteLen ->
+            let pname = PathName (castPtr ptr) (fromIntegral byteLen)
+            in act pname
+
+    withPathNames = contListMap withPathName withArray
+
+-- | Close a 'Watch' handle.
+--
+-- /Pre-release/
+--
+closeWatch :: Watch -> IO ()
+closeWatch (Watch h watchPtr mvar) = do
+    hClose h
+    closed <- takeMVar mvar
+    when (not closed) $ destroyWatch watchPtr
+    putMVar mvar True
+
+-------------------------------------------------------------------------------
+-- Raw events read from the watch file handle
+-------------------------------------------------------------------------------
+
+-- | An Event generated by the file system. Use the accessor functions to
+-- examine the event.
+--
+-- /Pre-release/
+--
+data Event = Event
+   { eventId :: Word64
+   , eventFlags :: Word32
+   , eventAbsPath :: Path
+   }
+
+-- XXX We can perhaps use parseD monad instance for fusing with parseMany? Need
+-- to measure the perf.
+--
+-- XXX should we use a magic in the header to avoid any issues due to
+-- misalignment of records? Can that ever happen?
+--
+readOneEvent :: Parser Word8 IO Event
+readOneEvent = do
+    arr <- PR.takeEQ 24 (A.createOf 24)
+    let arr1 = A.unsafeCast arr :: Array Word64
+        eid = A.unsafeGetIndex 0 arr1
+        eflags = A.unsafeGetIndex 1 arr1
+        pathLen = fromIntegral $ A.unsafeGetIndex 2 arr1
+    path <- PR.takeEQ pathLen (A.createOf pathLen)
+    return $ Event
+        { eventId = eid
+        , eventFlags = fromIntegral eflags
+        , eventAbsPath = Path.unsafeFromArray path
+        }
+
+watchToStream :: Watch -> Stream IO Event
+watchToStream (Watch handle _ _) =
+    S.catRights $ S.parseMany readOneEvent $ S.unfold FH.reader handle
+
+-- XXX Write tests for all the points in macOS specific behavior.
+--
+-- | Start monitoring a list of file system paths for file system events with
+-- the supplied configuration operation over the 'defaultConfig'. The paths
+-- could be files or directories.  When the path is a directory and recursive
+-- mode is set, the whole directory tree under it is watched recursively.
+-- Monitoring starts from the current time onwards.
+--
+-- Important notes for macOS specific behavior:
+--
+-- From the observed behavior it seems macOS watches the paths, whatever they
+-- are pointing to at any given point of time:
+--
+-- /Watch root deletion:/ If the the watch root is deleted and then recreated,
+-- the newly created file or directory is automatically watched.
+--
+-- /Watch root moved:/ If the watch root is moved to a new path, the object
+-- will no longer be watched unless the new path is also being watched and was
+-- pointing to an existing file at the time of starting the watch (see notes
+-- about non-existing paths below).
+--
+-- /Symbolic link watch root:/ If the path name to be watched is a symbolic
+-- link then the target of the link is watched instead of the symbolic link
+-- itself. It is equivalent to as if the target of the symbolic link itself was
+-- directly added to the watch API. That is, the symbolic link is resolved at
+-- the time of adding the watch.
+--
+-- Note that if a watched path is deleted and recreated as a symbolic link
+-- pointing to another path then the symbolic link file itself is watched, it
+-- won't be resolved. The symbolic link resolution happens only at the time of
+-- adding the watch.
+--
+-- /Non-existing Paths:/ If a watch is started on a non-existing path then the
+-- path is not watched even if it is created later.  The macOS API does not
+-- fail for a non-existing path.
+--
+-- If a non-existing path is watched with 'setRootPathEvents' then an
+-- 'isRootPathEvent' event is reported if the path is created later and the
+-- "path" field in the event is set to the dirname of the path rather than the
+-- full absolute path. This is the observed behavior on macOS 10.15.1.
+--
+-- @
+-- {-\# LANGUAGE MagicHash #-}
+-- watchWith
+--      ('setIgnoreSelf' 'True' . 'setRootPathEvents' 'True')
+--      [Path.fromString "path"]
+-- @
+--
+-- /Pre-release/
+--
+watchWith ::
+    (Config -> Config) -> NonEmpty Path -> Stream IO Event
+watchWith f paths = S.bracketIO before after watchToStream
+
+    where
+
+    before = openWatch (f defaultConfig) paths
+    after = closeWatch
+
+-- | Same as 'watchWith' using 'defaultConfig' and recursive mode.
+--
+-- >>> watchRecursive = watchWith id
+--
+watchRecursive :: NonEmpty Path -> Stream IO Event
+watchRecursive = watchWith id
+
+-- | Same as 'watchWith' using defaultConfig and non-recursive mode.
+--
+-- /Unimplemented/
+--
+watch :: NonEmpty Path -> Stream IO Event
+watch _paths = undefined
+
+-------------------------------------------------------------------------------
+-- Examine the event stream
+-------------------------------------------------------------------------------
+
+-- | Get the event id of an 'Event'.  Event-id is a monotonically increasing
+-- 64-bit integer identifying an event uniquely.
+--
+-- /Pre-release/
+--
+getEventId :: Event -> Word64
+getEventId Event{..} = eventId
+
+foreign import ccall safe
+    "FSEventStreamEventFlagEventIdsWrapped"
+    kFSEventStreamEventFlagEventIdsWrapped :: Word32
+
+-- | Determine whether the event id has wrapped. This is impossible on any
+-- traditional hardware in any reasonable amount of time unless the event-id
+-- starts from a very high value, because the event-id is a 64-bit integer.
+-- However, apple still recommends to check and handle this flag.
+--
+-- /macOS 10.5+/
+--
+-- /Pre-release/
+--
+isEventIdWrapped :: Event -> Bool
+isEventIdWrapped = getFlag kFSEventStreamEventFlagEventIdsWrapped
+
+-- | Get the absolute path of the file system object for which the event is
+-- generated. The path is a UTF-8 encoded array of bytes.
+--
+-- When the watch root is a symlink, the absolute path returned is via the real
+-- path of the root after resolving the symlink.
+--
+-- /Pre-release/
+--
+getAbsPath :: Event -> Path
+getAbsPath Event{..} = eventAbsPath
+
+-------------------------------------------------------------------------------
+-- Event types
+-------------------------------------------------------------------------------
+
+getFlag :: Word32 -> Event -> Bool
+getFlag mask Event{..} = eventFlags .&. mask /= 0
+
+-------------------------------------------------------------------------------
+-- Error events
+-------------------------------------------------------------------------------
+
+foreign import ccall safe
+    "FSEventStreamEventFlagMustScanSubDirs"
+    kFSEventStreamEventFlagMustScanSubDirs :: Word32
+
+-- | Apple documentation says that "If an event in a directory occurs at about
+-- the same time as one or more events in a subdirectory of that directory, the
+-- events may be coalesced into a single event." In that case you will recieve
+-- 'isEventsLost' event. In that case the path listed in the event is
+-- invalidated and you must rescan it to know the current state.
+--
+-- This event can also occur if a communication error (overflow) occurs in
+-- sending the event and the event gets dropped. In that case 'isKernelDropped'
+-- and/or 'isUserDropped' attributes will also be set.
+--
+-- /macOS 10.5+/
+--
+-- /Pre-release/
+--
+isEventsLost :: Event -> Bool
+isEventsLost = getFlag kFSEventStreamEventFlagMustScanSubDirs
+
+foreign import ccall safe
+    "FSEventStreamEventFlagKernelDropped"
+    kFSEventStreamEventFlagKernelDropped :: Word32
+
+-- | Did an event get dropped due to a kernel processing issue? Set only when
+-- 'isEventsLost' is also true.
+--
+-- /macOS 10.5+/
+--
+-- /Pre-release/
+--
+isKernelDropped :: Event -> Bool
+isKernelDropped = getFlag kFSEventStreamEventFlagKernelDropped
+
+foreign import ccall safe
+    "FSEventStreamEventFlagUserDropped"
+    kFSEventStreamEventFlagUserDropped :: Word32
+
+-- | Did an event get dropped due to a user process issue? Set only when
+-- 'isEventsLost' is also true.
+--
+-- /macOS 10.5+/
+--
+-- /Pre-release/
+--
+isUserDropped :: Event -> Bool
+isUserDropped = getFlag kFSEventStreamEventFlagUserDropped
+
+-------------------------------------------------------------------------------
+-- Global Sentinel Events
+-------------------------------------------------------------------------------
+
+foreign import ccall safe
+    "FSEventStreamEventFlagHistoryDone"
+    kFSEventStreamEventFlagHistoryDone :: Word32
+
+-- | Determine whether the event is a history done marker event. A history done
+-- event is generated when the historical events from before the current time
+-- are done. Historical events are generated when the "since" parameter in the
+-- watch config is set to before the current time.
+--
+-- /macOS 10.5+/
+--
+-- /Pre-release/
+--
+isHistoryDone :: Event -> Bool
+isHistoryDone = getFlag kFSEventStreamEventFlagHistoryDone
+
+-------------------------------------------------------------------------------
+-- Events affecting the watched path only
+-------------------------------------------------------------------------------
+
+foreign import ccall safe
+    "FSEventStreamEventFlagRootChanged"
+    kFSEventStreamEventFlagRootChanged :: Word32
+
+-- | Determine whether the event indicates a change of path of the monitored
+-- object itself. Note that the object may become unreachable or deleted after
+-- a change of path.
+--
+-- /Applicable only when 'setRootPathEvents' is 'True'/
+--
+-- /Occurs only for the watched path/
+--
+-- /macOS 10.5+/
+--
+-- /Pre-release/
+--
+isRootPathEvent :: Event -> Bool
+isRootPathEvent = getFlag kFSEventStreamEventFlagRootChanged
+
+-------------------------------------------------------------------------------
+-- Global events under the watched path
+-------------------------------------------------------------------------------
+
+foreign import ccall safe
+    "FSEventStreamEventFlagMount"
+    kFSEventStreamEventFlagMount :: Word32
+
+-- | Determine whether the event is a mount event. A mount event is generated
+-- if a volume is mounted under the path being watched.
+--
+-- /macOS 10.5+/
+--
+-- /Pre-release/
+--
+isMounted :: Event -> Bool
+isMounted = getFlag kFSEventStreamEventFlagMount
+
+foreign import ccall safe
+    "FSEventStreamEventFlagUnmount"
+    kFSEventStreamEventFlagUnmount :: Word32
+
+-- | Determine whether the event is an unmount event. An unmount event is
+-- generated if a volume mounted under the path being watched is unmounted.
+--
+-- /macOS 10.5+/
+--
+-- /Pre-release/
+--
+isUnmounted :: Event -> Bool
+isUnmounted = getFlag kFSEventStreamEventFlagUnmount
+
+-------------------------------------------------------------------------------
+-- Metadata change Events (applicable only when 'setFileEvents' is 'True')
+-------------------------------------------------------------------------------
+
+foreign import ccall safe
+    "FSEventStreamEventFlagItemChangeOwner"
+    kFSEventStreamEventFlagItemChangeOwner :: Word32
+
+-- | Determine whether the event is ownership, group, permissions or ACL change
+-- event of an object contained within the monitored path.
+--
+-- Note that this event may be generated even if the metadata is changed to the
+-- same value again.
+--
+-- /Applicable only when 'setFileEvents' is 'True'/
+--
+-- /Can occur for watched path or a file inside it/
+--
+-- /macOS 10.7+/
+--
+-- /Pre-release/
+--
+isSecurityModified :: Event -> Bool
+isSecurityModified = getFlag kFSEventStreamEventFlagItemChangeOwner
+
+foreign import ccall safe
+    "FSEventStreamEventFlagItemInodeMetaMod"
+    kFSEventStreamEventFlagItemInodeMetaMod :: Word32
+
+-- | Determine whether the event indicates inode metadata change for an object
+-- contained within the monitored path. This event is generated when inode
+-- attributes other than the owner, group or permissions are changed e.g. file
+-- modification time. It does not occur when the link count of a file changes
+-- (as of macOS 10.15.1).
+--
+-- /Applicable only when 'setFileEvents' is 'True'/
+--
+-- /Can occur for watched path or a file inside it/
+--
+-- /macOS 10.7+/
+--
+-- /Pre-release/
+--
+isAttrsModified :: Event -> Bool
+isAttrsModified = getFlag kFSEventStreamEventFlagItemInodeMetaMod
+
+foreign import ccall safe
+    "FSEventStreamEventFlagItemFinderInfoMod"
+    kFSEventStreamEventFlagItemFinderInfoMod :: Word32
+
+-- | Determine whether the event indicates finder information metadata change
+-- for an object contained within the monitored path.
+--
+-- /Applicable only when 'setFileEvents' is 'True'/
+--
+-- /macOS 10.7+/
+--
+-- /Pre-release/
+--
+isFinderInfoModified :: Event -> Bool
+isFinderInfoModified = getFlag kFSEventStreamEventFlagItemFinderInfoMod
+
+foreign import ccall safe
+    "FSEventStreamEventFlagItemXattrMod"
+    kFSEventStreamEventFlagItemXattrMod :: Word32
+
+-- | Determine whether the event indicates extended attributes metadata change
+-- for an object contained within the monitored path.
+--
+-- /Applicable only when 'setFileEvents' is 'True'/
+--
+-- /Can occur for watched path or a file inside it/
+--
+-- /macOS 10.7+/
+--
+-- /Pre-release/
+--
+isXAttrsModified :: Event -> Bool
+isXAttrsModified = getFlag kFSEventStreamEventFlagItemXattrMod
+
+-------------------------------------------------------------------------------
+-- CRUD Events (applicable only when 'setFileEvents' is 'True')
+-------------------------------------------------------------------------------
+
+foreign import ccall safe
+    "FSEventStreamEventFlagItemCreated"
+    kFSEventStreamEventFlagItemCreated :: Word32
+
+-- | Determine whether the event indicates creation of an object within the
+-- monitored path. This event is generated when any file system object other
+-- than a hard link is created.  On hard linking only an 'isAttrsModified'
+-- event on the directory is generated, it is not a create event. However, when
+-- a hard link is deleted 'isDeleted' and 'isHardLink' both are true.
+--
+-- This event can occur for the watched path if the path was deleted/moved and
+-- created again (tested on macOS 10.15.1). However, if a watch is started on a
+-- non-existing path and the path is created later, then this event is not
+-- generated, the path is not watched.
+--
+-- BUGS: On 10.15.1 when we use a "touch x" to create a file for the first time
+-- only an 'isAttrsModified' event occurs and there is no 'isCreated'
+-- event. However, this seems to have been fixed on 10.15.6.
+--
+-- /Applicable only when 'setFileEvents' is 'True'/
+--
+-- /Can occur for watched path or a file inside it/
+--
+-- /macOS 10.7+/
+--
+-- /Pre-release/
+--
+isCreated :: Event -> Bool
+isCreated = getFlag kFSEventStreamEventFlagItemCreated
+
+foreign import ccall safe
+    "FSEventStreamEventFlagItemRemoved"
+    kFSEventStreamEventFlagItemRemoved :: Word32
+
+-- | Determine whether the event indicates deletion of an object within the
+-- monitored path. This is true when a file or a hardlink is deleted.
+--
+-- Applicable only when 'setFileEvents' is 'True'.
+--
+-- /Can occur for watched path or a file inside it/
+--
+-- /macOS 10.7+/
+--
+-- /Pre-release/
+--
+isDeleted :: Event -> Bool
+isDeleted = getFlag kFSEventStreamEventFlagItemRemoved
+
+foreign import ccall safe
+    "FSEventStreamEventFlagItemRenamed"
+    kFSEventStreamEventFlagItemRenamed :: Word32
+
+-- | Determine whether the event indicates rename of an object within the
+-- monitored path. This event is generated when a file is renamed within the
+-- watched directory or if it is moved out of or in the watched directory.
+--
+-- /Applicable only when 'setFileEvents' is 'True'/
+--
+-- /Can occur for watched path or a file inside it/
+--
+-- /macOS 10.7+/
+--
+-- /Pre-release/
+--
+isMoved :: Event -> Bool
+isMoved = getFlag kFSEventStreamEventFlagItemRenamed
+
+foreign import ccall safe
+    "FSEventStreamEventFlagItemModified"
+    kFSEventStreamEventFlagItemModified :: Word32
+
+-- | Determine whether the event indicates modification of an object within the
+-- monitored path. This event is generated only for files and not directories.
+--
+-- Applicable only when 'setFileEvents' is 'True'.
+--
+-- /macOS 10.7+/
+--
+-- /Pre-release/
+--
+isModified :: Event -> Bool
+isModified = getFlag kFSEventStreamEventFlagItemModified
+
+#if HAVE_DECL_KFSEVENTSTREAMEVENTFLAGITEMCLONED
+foreign import ccall safe
+    "FSEventStreamEventFlagItemCloned"
+    kFSEventStreamEventFlagItemCloned :: Word32
+
+-- | Determine whether the event indicates cloning of an object within the
+-- monitored path. The "Duplicate" command in the "File" menu of the "Finder"
+-- application generates a "clone" event.
+--
+-- Applicable only when 'setFileEvents' is 'True'.
+--
+-- /macOS 10.13+/
+--
+-- /Pre-release/
+--
+isCloned :: Event -> Bool
+isCloned = getFlag kFSEventStreamEventFlagItemCloned
+#endif
+
+-------------------------------------------------------------------------------
+-- Information about path type (applicable only when 'setFileEvents' is 'True')
+-------------------------------------------------------------------------------
+
+foreign import ccall safe
+    "FSEventStreamEventFlagItemIsDir"
+    kFSEventStreamEventFlagItemIsDir :: Word32
+
+-- | Determine whether the event is for a directory path.
+--
+-- Applicable only when 'setFileEvents' is 'True'.
+--
+-- /macOS 10.7+/
+--
+-- /Pre-release/
+--
+isDir :: Event -> Bool
+isDir = getFlag kFSEventStreamEventFlagItemIsDir
+
+foreign import ccall safe
+    "FSEventStreamEventFlagItemIsFile"
+    kFSEventStreamEventFlagItemIsFile :: Word32
+
+-- | Determine whether the event is for a file path.
+--
+-- Applicable only when 'setFileEvents' is 'True'.
+--
+-- /macOS 10.7+/
+--
+-- /Pre-release/
+--
+isFile :: Event -> Bool
+isFile = getFlag kFSEventStreamEventFlagItemIsFile
+
+foreign import ccall safe
+    "FSEventStreamEventFlagItemIsSymlink"
+    kFSEventStreamEventFlagItemIsSymlink :: Word32
+
+-- | Determine whether the event is for a symbolic link path.
+--
+-- Applicable only when 'setFileEvents' is 'True'.
+--
+-- /macOS 10.7+/
+--
+-- /Pre-release/
+--
+isSymLink :: Event -> Bool
+isSymLink = getFlag kFSEventStreamEventFlagItemIsSymlink
+
+#if HAVE_DECL_KFSEVENTSTREAMEVENTFLAGITEMISHARDLINK
+foreign import ccall safe
+    "FSEventStreamEventFlagItemIsHardlink"
+    kFSEventStreamEventFlagItemIsHardlink :: Word32
+
+-- | Determine whether the event is for a file with more than one hard link.
+-- When 'isFile' is true we can check for 'isHardLink'. Note that 'isHardLink'
+-- is not true when a hard link is created, however, it is true when a file
+-- which has or had more than one link in the past is removed. This is not true
+-- if a file never had more than one link.
+--
+-- Applicable only when 'setFileEvents' is 'True'.
+--
+-- /macOS 10.10+/
+--
+-- /Pre-release/
+--
+isHardLink :: Event -> Bool
+isHardLink = getFlag kFSEventStreamEventFlagItemIsHardlink
+
+foreign import ccall safe
+    "FSEventStreamEventFlagItemIsLastHardlink"
+     kFSEventStreamEventFlagItemIsLastHardlink :: Word32
+
+-- | Determine whether the event is for a hard link path with only one hard
+-- link.  If 'isHardLink' is true then we can check for 'isLastHardLink'.  This
+-- is true when a file has had more than one link and now the last link is
+-- removed. In that case both 'isHardLink' and 'isLastHardLink" would be true.
+--
+-- Applicable only when 'setFileEvents' is 'True'.
+--
+-- /macOS 10.10+/
+--
+-- /Pre-release/
+--
+isLastHardLink :: Event -> Bool
+isLastHardLink = getFlag kFSEventStreamEventFlagItemIsLastHardlink
+#endif
+
+-------------------------------------------------------------------------------
+-- Debugging
+-------------------------------------------------------------------------------
+
+-- | Convert an 'Event' record to a String representation.
+showEvent :: Event -> String
+showEvent ev@Event{..} =
+    let path = Path.toString eventAbsPath
+    in "--------------------------"
+        ++ "\nId = " ++ show eventId
+        ++ "\nPath = " ++ show path
+        ++ "\nFlags " ++ show eventFlags
+
+        ++ showev isEventsLost "MustScanSubdirs"
+        ++ showev isKernelDropped "KernelDropped"
+        ++ showev isUserDropped "UserDropped"
+
+        ++ showev isRootPathEvent "RootPathEvent"
+        ++ showev isMounted "Mounted"
+        ++ showev isUnmounted "Unmounted"
+        ++ showev isHistoryDone "HistoryDone"
+
+        ++ showev isSecurityModified "SecurityModified"
+        ++ showev isAttrsModified "AttrsModified"
+        ++ showev isFinderInfoModified "FinderInfoChanged"
+        ++ showev isXAttrsModified "XAttrsModified"
+
+        ++ showev isCreated "Created"
+        ++ showev isDeleted "Deleted"
+        ++ showev isModified "Modified"
+        ++ showev isMoved "Moved"
+#if HAVE_DECL_KFSEVENTSTREAMEVENTFLAGITEMCLONED
+        ++ showev isCloned "Cloned"
+#endif
+
+        ++ showev isDir "Dir"
+        ++ showev isFile "File"
+        ++ showev isSymLink "SymLink"
+#if HAVE_DECL_KFSEVENTSTREAMEVENTFLAGITEMISHARDLINK
+        ++ showev isHardLink "HardLink"
+        ++ showev isLastHardLink "LastHardLink"
+#endif
+        ++ "\n"
+
+        where showev f str = if f ev then "\n" ++ str else ""
+#else
+module Streamly.Internal.FS.Event.Darwin () where
+#warning "Autoconf did not find the definition \
+kFSEventStreamCreateFlagFileEvents in Darwin header files.\
+Do you have Cocoa framework header files installed?\
+Not compiling the Streamly.Internal.FS.Event.Darwin module. \
+Programs depending on this module may not compile. \
+Check if HAVE_DECL_KFSEVENTSTREAMCREATEFLAGFILEEVENTS is defined in config.h \
+generated from src/config.h.in"
+#endif
diff --git a/src/Streamly/Internal/FS/Event/Linux.hs b/src/Streamly/Internal/FS/Event/Linux.hs
new file mode 100644
--- /dev/null
+++ b/src/Streamly/Internal/FS/Event/Linux.hs
@@ -0,0 +1,1278 @@
+-- |
+-- Module      : Streamly.Internal.FS.Event.Linux
+-- Copyright   : (c) 2020 Composewell Technologies
+-- License     : BSD-3-Clause
+-- Maintainer  : streamly@composewell.com
+-- Stability   : experimental
+-- Portability : GHC
+--
+-- =Overview
+--
+-- Use 'watchPaths' with a list of file system paths you want to watch as
+-- argument. It returns a stream of 'Event' representing the file system events
+-- occurring under the watched paths.
+--
+-- @
+-- Stream.mapM_ (putStrLn . 'showEvent') $ 'watchPaths' [Path.fromString "dir"]
+-- @
+--
+-- 'Event' is an opaque type. Accessor functions (e.g. 'showEvent' above)
+-- provided in this module are used to determine the attributes of the event.
+--
+-- Identical successive events may be coalesced into a single event.
+--
+-- =Design notes
+--
+-- For reference documentation see:
+--
+-- * <https://man7.org/linux/man-pages/man7/inotify.7.html inotify man page>
+--
+-- We try to keep the macOS\/Linux/Windows event handling APIs and defaults
+-- semantically and syntactically as close as possible.
+--
+-- =BUGs
+--
+-- When testing on Linux Kernel version @5.3.0-53-generic #47-Ubuntu@, the last
+-- event for the root path seems to be delayed until one more event occurs.
+--
+-- = Differences between macOS and Linux APIs:
+--
+-- 1. macOS watch is based on the path provided to it, if the path is
+-- deleted and recreated it will still be watched, if the path moves to another
+-- path it won't be watched anymore. Whereas Linux watch is based on a handle
+-- to the path, if the path is deleted and recreated it won't be watched, if
+-- the path moves to another it can still be watched (though this is
+-- configurable).
+--
+-- 2. macOS watches the directory hierarchy recursively, Linux watches only one
+-- level of dir, recursive watch has to be built in user space by watching for
+-- create events and adding the new directories to the watch. Not sure how this
+-- will scale for too many paths.
+--
+-- 3. In macOS the path of the subject of the event is absolute, in Linux the
+-- path is the name of the object inside the dir being watched.
+--
+-- 4. On Linux 'watchPaths' fails if a path does not exist, on macOS it does
+-- not fail.
+
+#include "config.h"
+
+#if HAVE_DECL_IN_EXCL_UNLINK
+module Streamly.Internal.FS.Event.Linux
+    (
+    -- * Subscribing to events
+
+    -- ** Default configuration
+      Config (..)
+    , defaultConfig
+
+    -- ** Watch Behavior
+    , setRecursiveMode
+    , setFollowSymLinks
+    , setUnwatchMoved
+    , setOneShot
+    , setOnlyDir
+    , WhenExists (..)
+    , setWhenExists
+
+    -- ** Events of Interest
+    -- *** Root Path Events
+    , setRootDeleted
+    , setRootMoved
+    , setRootPathEvents
+
+    -- *** Item Level Metadata change
+    , setAttrsModified
+
+    -- *** Item Level Access
+    , setAccessed
+    , setOpened
+    , setWriteClosed
+    , setNonWriteClosed
+
+    -- *** Item CRUD events
+    , setCreated
+    , setDeleted
+    , setMovedFrom
+    , setMovedTo
+    , setModified
+
+    , setAllEvents
+
+    -- ** Watch APIs
+    , watch
+    , watchRecursive
+    , watchWith
+
+    -- Low level watch APIs
+    , addToWatch
+    , removeFromWatch
+
+    -- * Handling Events
+    , Event(..)
+    , getRoot
+    , getRelPath
+    , getAbsPath
+    , getCookie
+
+    -- ** Root Level Events
+    , isRootPathEvent
+    , isRootUnwatched
+    , isRootDeleted
+    , isRootMoved
+    , isRootUnmounted
+
+    -- ** Item Level Metadata change
+    , isAttrsModified
+
+    -- ** Item Level Access
+    , isAccessed
+    , isOpened
+    , isWriteClosed
+    , isNonWriteClosed
+
+    -- ** Item Level CRUD events
+    , isCreated
+    , isDeleted
+    , isMovedFrom
+    , isMovedTo
+    , isMoved
+    , isModified
+
+    -- ** Item Path info
+    , isDir
+
+    -- ** Exception Conditions
+    , isEventsLost
+
+    -- * Debugging
+    , showEvent
+    )
+where
+
+import Control.Monad (void, when)
+import Data.Bits ((.|.), (.&.), complement)
+import Data.Foldable (foldlM)
+import Data.IntMap.Lazy (IntMap)
+import Data.IORef (IORef, newIORef, readIORef, writeIORef, modifyIORef)
+import Data.List.NonEmpty (NonEmpty)
+#if !(MIN_VERSION_base(4,13,0))
+import Data.Semigroup (Semigroup(..))
+#endif
+import Data.Word (Word8, Word32)
+import Foreign.C.Error (throwErrnoIfMinus1)
+import Foreign.C.String (CString)
+import Foreign.C.Types (CInt(..), CUInt(..))
+import Foreign.Ptr (Ptr)
+import Foreign.Storable (peek, peekByteOff, sizeOf)
+import GHC.IO.Device (IODeviceType(Stream))
+import GHC.IO.FD (fdFD, FD(..))
+import GHC.IO.Handle.FD (mkHandleFromFD)
+import Streamly.Data.Stream (Stream)
+import Streamly.Data.Parser (Parser)
+import System.Directory (doesDirectoryExist)
+import System.IO (Handle, hClose, IOMode(ReadMode))
+import GHC.IO.Handle.FD (handleToFd)
+
+import Streamly.Internal.Data.Array (byteLength)
+import Streamly.Internal.FileSystem.Path (Path)
+
+import qualified Data.IntMap.Lazy as Map
+import qualified Data.List.NonEmpty as NonEmpty
+import qualified Streamly.Data.Fold as FL
+import qualified Streamly.Data.Array as A (createOf)
+import qualified Streamly.Data.Stream as S
+import qualified Streamly.FileSystem.Handle as FH
+import qualified Streamly.Internal.FileSystem.Path as Path
+
+import qualified Streamly.Internal.Data.Array as A
+    ( asCStringUnsafe, unsafePinnedAsPtr
+    )
+import qualified Streamly.Internal.FileSystem.DirIO as Dir (readDirs)
+import qualified Streamly.Internal.Data.Parser as PR
+    (takeEQ, fromEffect, fromFold)
+
+-------------------------------------------------------------------------------
+-- Subscription to events
+-------------------------------------------------------------------------------
+
+-- | Watch configuration, used to specify the events of interest and the
+-- behavior of the watch.
+--
+-- /Pre-release/
+--
+data Config = Config
+    { watchRec :: Bool
+    , createFlags :: Word32
+    }
+
+-------------------------------------------------------------------------------
+-- Boolean settings
+-------------------------------------------------------------------------------
+
+setFlag :: Word32 -> Bool -> Config -> Config
+setFlag mask status cfg@Config{..} =
+    let flags =
+            if status
+            then createFlags .|. mask
+            else createFlags .&. complement mask
+    in cfg {createFlags = flags}
+
+-------------------------------------------------------------------------------
+-- Settings
+-------------------------------------------------------------------------------
+
+-- | Watch the whole directory tree recursively instead of watching just one
+-- level of directory.
+--
+-- /default: False/
+--
+-- /Pre-release/
+--
+setRecursiveMode :: Bool -> Config -> Config
+setRecursiveMode recursive cfg@Config{} = cfg {watchRec = recursive}
+
+foreign import capi
+    "sys/inotify.h value IN_DONT_FOLLOW" iN_DONT_FOLLOW :: Word32
+
+-- | If the pathname to be watched is a symbolic link then watch the target of
+-- the symbolic link instead of the symbolic link itself.
+--
+-- Note that the path location in the events is through the original symbolic
+-- link path rather than the resolved path.
+--
+-- /default: True/
+--
+-- /Pre-release/
+--
+setFollowSymLinks :: Bool -> Config -> Config
+setFollowSymLinks s = setFlag iN_DONT_FOLLOW (not s)
+
+foreign import capi
+    "sys/inotify.h value IN_EXCL_UNLINK" iN_EXCL_UNLINK :: Word32
+
+-- | If an object moves out of the directory being watched then stop watching
+-- it.
+--
+-- /default: True/
+--
+-- /Pre-release/
+--
+setUnwatchMoved :: Bool -> Config -> Config
+setUnwatchMoved = setFlag iN_EXCL_UNLINK
+
+#if HAVE_DECL_IN_MASK_CREATE
+foreign import capi
+    "sys/inotify.h value IN_MASK_CREATE" iN_MASK_CREATE :: Word32
+#endif
+
+foreign import capi
+    "sys/inotify.h value IN_MASK_ADD" iN_MASK_ADD :: Word32
+
+-- | What to do if a watch already exists when 'openWatch' or 'addToWatch' is
+-- called for a path.
+--
+-- /Pre-release/
+--
+data WhenExists =
+      AddIfExists -- ^ Do not set an existing setting to 'False' only set to 'True'
+    | ReplaceIfExists -- ^ Replace the existing settings with new settings
+#if HAVE_DECL_IN_MASK_CREATE
+    | FailIfExists -- ^ Fail the API
+#endif
+
+-- | When adding a new path to the watch, specify what to do if a watch already
+-- exists on that path.
+--
+-- /default: FailIfExists/
+--
+-- /Pre-release/
+--
+setWhenExists :: WhenExists -> Config -> Config
+setWhenExists val cfg =
+    case val of
+        AddIfExists -> setFlag iN_MASK_ADD True cfg
+        ReplaceIfExists -> setFlag iN_MASK_ADD False cfg
+#if HAVE_DECL_IN_MASK_CREATE
+        FailIfExists -> setFlag iN_MASK_CREATE True cfg
+#endif
+
+foreign import capi
+    "sys/inotify.h value IN_ONESHOT" iN_ONESHOT :: Word32
+
+-- | Watch the object only for one event and then remove it from the watch.
+--
+-- /default: False/
+--
+-- /Pre-release/
+--
+setOneShot :: Bool -> Config -> Config
+setOneShot = setFlag iN_ONESHOT
+
+foreign import capi
+    "sys/inotify.h value IN_ONLYDIR" iN_ONLYDIR :: Word32
+
+-- | Watch the object only if it is a directory. This provides a race-free way
+-- to ensure that the watched object is a directory.
+--
+-- /default: False/
+--
+-- /Pre-release/
+--
+setOnlyDir :: Bool -> Config -> Config
+setOnlyDir = setFlag iN_ONLYDIR
+
+-------------------------------------------------------------------------------
+-- Event types that can occur
+-------------------------------------------------------------------------------
+
+foreign import capi
+    "sys/inotify.h value IN_DELETE_SELF" iN_DELETE_SELF :: Word32
+
+-- | Report when the watched path itself gets deleted.
+--
+-- /default: True/
+--
+-- /Pre-release/
+--
+setRootDeleted :: Bool -> Config -> Config
+setRootDeleted = setFlag iN_DELETE_SELF
+
+foreign import capi
+    "sys/inotify.h value IN_MOVE_SELF" iN_MOVE_SELF :: Word32
+
+-- | Report when the watched root path itself gets renamed.
+--
+-- /default: True/
+--
+-- /Pre-release/
+--
+setRootMoved :: Bool -> Config -> Config
+setRootMoved = setFlag iN_MOVE_SELF
+
+-- | Report when the watched root path itself gets deleted or renamed.
+--
+-- /default: True/
+--
+-- /Pre-release/
+--
+setRootPathEvents :: Bool -> Config -> Config
+setRootPathEvents = setFlag (iN_DELETE_SELF .|. iN_MOVE_SELF)
+
+foreign import capi
+    "sys/inotify.h value IN_ATTRIB" iN_ATTRIB :: Word32
+
+-- | Report when the metadata e.g. owner, permission modes, modifications times
+-- of an object changes.
+--
+-- /default: True/
+--
+-- /Pre-release/
+--
+setAttrsModified :: Bool -> Config -> Config
+setAttrsModified = setFlag iN_ATTRIB
+
+foreign import capi
+    "sys/inotify.h value IN_ACCESS" iN_ACCESS :: Word32
+
+-- | Report when a file is accessed.
+--
+-- /default: True/
+--
+-- /Pre-release/
+--
+setAccessed :: Bool -> Config -> Config
+setAccessed = setFlag iN_ACCESS
+
+foreign import capi
+    "sys/inotify.h value IN_OPEN" iN_OPEN :: Word32
+
+-- | Report when a file is opened.
+--
+-- /default: True/
+--
+-- /Pre-release/
+--
+setOpened :: Bool -> Config -> Config
+setOpened = setFlag iN_OPEN
+
+foreign import capi
+    "sys/inotify.h value IN_CLOSE_WRITE" iN_CLOSE_WRITE :: Word32
+
+-- | Report when a file that was opened for writes is closed.
+--
+-- /default: True/
+--
+-- /Pre-release/
+--
+setWriteClosed :: Bool -> Config -> Config
+setWriteClosed = setFlag iN_CLOSE_WRITE
+
+foreign import capi
+    "sys/inotify.h value IN_CLOSE_NOWRITE" iN_CLOSE_NOWRITE :: Word32
+
+-- | Report when a file that was opened for not writing is closed.
+--
+-- /default: True/
+--
+-- /Pre-release/
+--
+setNonWriteClosed :: Bool -> Config -> Config
+setNonWriteClosed = setFlag iN_CLOSE_NOWRITE
+
+foreign import capi
+    "sys/inotify.h value IN_CREATE" iN_CREATE :: Word32
+
+-- | Report when a file is created.
+--
+-- /default: True/
+--
+-- /Pre-release/
+--
+setCreated :: Bool -> Config -> Config
+setCreated = setFlag iN_CREATE
+
+foreign import capi
+    "sys/inotify.h value IN_DELETE" iN_DELETE :: Word32
+
+-- | Report when a file is deleted.
+--
+-- /default: True/
+--
+-- /Pre-release/
+--
+setDeleted :: Bool -> Config -> Config
+setDeleted = setFlag iN_DELETE
+
+foreign import capi
+    "sys/inotify.h value IN_MOVED_FROM" iN_MOVED_FROM :: Word32
+
+-- | Report the source of a move.
+--
+-- /default: True/
+--
+-- /Pre-release/
+--
+setMovedFrom :: Bool -> Config -> Config
+setMovedFrom = setFlag iN_MOVED_FROM
+
+foreign import capi
+    "sys/inotify.h value IN_MOVED_TO" iN_MOVED_TO :: Word32
+
+-- | Report the target of a move.
+--
+-- /default: True/
+--
+-- /Pre-release/
+--
+setMovedTo :: Bool -> Config -> Config
+setMovedTo = setFlag iN_MOVED_TO
+
+foreign import capi
+    "sys/inotify.h value IN_MODIFY" iN_MODIFY :: Word32
+
+-- | Report when a file is modified.
+--
+-- /default: True/
+--
+-- /Pre-release/
+--
+setModified :: Bool -> Config -> Config
+setModified = setFlag iN_MODIFY
+
+-- | Set all tunable events 'True' or 'False'. Equivalent to setting:
+--
+-- * setRootDeleted
+-- * setRootMoved
+-- * setAttrsModified
+-- * setAccessed
+-- * setOpened
+-- * setWriteClosed
+-- * setNonWriteClosed
+-- * setCreated
+-- * setDeleted
+-- * setMovedFrom
+-- * setMovedTo
+-- * setModified
+--
+-- /Pre-release/
+--
+setAllEvents :: Bool -> Config -> Config
+setAllEvents s =
+      setRootDeleted s
+    . setRootMoved s
+    . setAttrsModified s
+    . setAccessed s
+    . setOpened s
+    . setWriteClosed s
+    . setNonWriteClosed s
+    . setCreated s
+    . setDeleted s
+    . setMovedFrom s
+    . setMovedTo s
+    . setModified s
+
+-------------------------------------------------------------------------------
+-- Default config
+-------------------------------------------------------------------------------
+
+-- The defaults are set in such a way that the behavior on macOS and Linux is
+-- as much compatible as possible.
+--
+-- | The default configuration settings are:
+--
+-- * 'setFollowSymLinks' 'True'
+-- * 'setUnwatchMoved' 'True'
+-- * 'setOneShot' 'False'
+-- * 'setOnlyDir' 'False'
+-- * 'setWhenExists' 'AddIfExists'
+--
+-- The tunable events enabled by default are:
+--
+-- * setCreated True
+-- * setDeleted True
+-- * setMovedFrom True
+-- * setMovedTo True
+-- * setModified True
+--
+-- /Pre-release/
+--
+defaultConfig :: Config
+defaultConfig =
+      setWhenExists AddIfExists
+    $ setCreated True
+    $ setDeleted True
+    $ setMovedFrom True
+    $ setMovedTo True
+    $ setModified True
+    $ Config
+        { watchRec = False
+        , createFlags = 0
+        }
+
+-------------------------------------------------------------------------------
+-- Path representation for events
+-------------------------------------------------------------------------------
+
+type PathRep =
+    ( Path       -- Absolute path of the watch root
+    , Maybe Path -- Path of subdir relative to watch root
+    )
+
+{-# INLINE combinePathRep #-}
+combinePathRep :: PathRep -> Path
+combinePathRep (root, Nothing) = root
+combinePathRep (root, Just sub) = Path.join root sub
+
+{-# INLINE addSub #-}
+addSub :: PathRep -> Path -> PathRep
+addSub (root, Nothing) sub = (root, Just sub)
+addSub (root, Just sub0) sub1 = (root, Just (Path.join sub0 sub1))
+
+{-# INLINE getRepRoot #-}
+getRepRoot :: PathRep -> Path
+getRepRoot = fst
+
+{-# INLINE getRepSub #-}
+getRepSub :: PathRep -> Maybe Path
+getRepSub = snd
+
+-------------------------------------------------------------------------------
+-- Open an event stream
+-------------------------------------------------------------------------------
+
+-- | A handle for a watch.
+data Watch =
+    Watch
+        Handle                  -- File handle for the watch
+        (IORef
+            (IntMap             -- Key is the watch descriptor
+                PathRep
+            )
+        )
+
+-- Instead of using the watch descriptor we can provide APIs that use the path
+-- itself to identify the watch. That will require us to maintain a map from wd
+-- to path in the Watch handle.
+
+newtype WD = WD CInt deriving Show
+
+-- XXX Use inotify_init1? and IN_NONBLOCK?
+foreign import ccall unsafe
+    "sys/inotify.h inotify_init" c_inotify_init :: IO CInt
+
+-- | Create a 'Watch' handle. 'addToWatch' can be used to add paths being
+-- monitored by this watch.
+--
+-- /Pre-release/
+--
+createWatch :: IO Watch
+createWatch = do
+    rawfd <- throwErrnoIfMinus1 "createWatch" c_inotify_init
+    -- We could use fdToHandle but it cannot determine the fd type
+    -- automatically for the inotify fd because fdStat fails for Stream type
+    -- fd.
+    --
+    -- Do not use mkFD as it locks a regular file causing "resource busy" error
+    -- in some test cases.
+    let fd =
+            FD
+                { fdFD = rawfd
+#if !defined(mingw32_HOST_OS)
+                , fdIsNonBlocking = 0
+#else
+                , fdIsSocket_ = 0
+#endif
+              }
+
+    -- XXX Do we need non-blocking IO?
+    -- With non-blocking IO it fails because GHC-9.10 uses fdStat in
+    -- FD.setNonBlockingMode to determine the fd type which fails for Stream
+    -- type fd. However, without non-blocking IO "select" has a limitation on
+    -- the number of FDs being watched (1024).
+    h <-
+        mkHandleFromFD
+           fd
+           Stream
+           ("<createWatch fd: " ++ show fd ++ ">")
+           ReadMode
+           False    -- use non-blocking IO
+           Nothing -- TextEncoding (binary)
+    emptyMapRef <- newIORef Map.empty
+    return $ Watch h emptyMapRef
+
+foreign import ccall unsafe
+    "sys/inotify.h inotify_add_watch" c_inotify_add_watch
+        :: CInt -> CString -> CUInt -> IO CInt
+
+-- | @addToWatch cfg watch root subpath@ adds @subpath@ to the list of paths
+-- being monitored under @root@ via the watch handle @watch@.  @root@ must be
+-- an absolute path and @subpath@ must be relative to @root@.
+--
+-- /Pre-release/
+--
+addToWatch :: Config -> Watch -> PathRep -> IO ()
+addToWatch cfg@Config{..} watch0@(Watch handle wdMap) prep = do
+    -- XXX do not add if the path is already added
+    -- XXX if the watch is added by the scan and not via an event we can
+    -- generate a create event assuming that the create may have been lost. We
+    -- can also mark in the map that this entry was added by the scan. So if an
+    -- actual create event later comes and tries to add this again then we can
+    -- ignore that and drop the create event to avoid duplicate create, because
+    -- we have already emitted it.
+    --
+    -- When a directory is added by the scan we should also emit create events
+    -- for files that may have got added to the dir. However, such create
+    -- events may get duplicated because of a race between the scan generated
+    -- versus real events.
+    --
+    -- Or we may distinguish between scan generated events and real events so
+    -- that the application can assume that other events may been lost and
+    -- handle it. For example, if it is a dir create the application can read
+    -- the dir to scan the files in it.
+    --
+    let absPath = combinePathRep prep
+    --    showPathRep (root, Nothing) = "root = " ++ Path.toString root
+    --    showPathRep (root, Just sub) =
+    --        "root = " ++ Path.toString root ++ " sub = " ++ Path.toString sub
+    -- putStrLn $ showPathRep prep ++ " absPath = " ++ Path.toString absPath
+
+    fd <- handleToFd handle
+
+    -- XXX we need to tolerate an error where we are adding a watch for a
+    -- non-existing file because the file may have got deleted by the time we
+    -- added the watch. Perhaps we can have a flag in config for this and keep
+    -- the default value to tolerate the error.
+    --
+    -- XXX The file may have even got deleted and then recreated which we will
+    -- never get to know, document this.
+    wd <- A.asCStringUnsafe (Path.toArray absPath) $ \pathPtr ->
+            throwErrnoIfMinus1 ("addToWatch: " ++ Path.toString absPath) $
+                c_inotify_add_watch (fdFD fd) pathPtr (CUInt createFlags)
+
+    -- We add the parent first so that we start getting events for any new
+    -- creates and add the new subdirectories on creates while we are adding
+    -- the children.
+    modifyIORef wdMap (Map.insert (fromIntegral wd) prep)
+
+    -- Now add the children. If we missed any creates while we were adding the
+    -- parent, this will make sure they are added too.
+    --
+    -- XXX Ensure that we generate events that we may have missed while we were
+    -- adding the dirs. That may generate spurious events though.
+    --
+    -- XXX Are the following comments obselete?
+    -- XXX readDirs currently uses paths as String, we need to convert it
+    -- to "/" separated by byte arrays.
+    -- XXX Need a FileSystem.Stat module to remove this
+    pathIsDir <- doesDirectoryExist (Path.toString absPath)
+    when (watchRec && pathIsDir) $ do
+        let f = addToWatch cfg watch0 . addSub prep
+            in S.fold (FL.drainMapM f) $ Dir.readDirs id absPath
+
+foreign import ccall unsafe
+    "sys/inotify.h inotify_rm_watch" c_inotify_rm_watch
+        :: CInt -> CInt -> IO CInt
+
+-- | Remove an absolute root path from a 'Watch', if a path was moved after
+-- adding you need to provide the original path which was used to add the
+-- Watch.
+--
+-- /Pre-release/
+--
+removeFromWatch :: Watch -> Path -> IO ()
+removeFromWatch (Watch handle wdMap) root = do
+    fd <- handleToFd handle
+    km <- readIORef wdMap
+    wdMap1 <- foldlM (step fd) Map.empty (Map.toList km)
+    writeIORef wdMap wdMap1
+
+    where
+
+    step fd newMap (wd, v) = do
+        -- XXX Path is currently not guaranteed to be normalized.
+        -- See: https://github.com/composewell/streamly/issues/2888
+        if Path.toArray (getRepRoot v) == Path.toArray root
+        then do
+            let err = "removeFromWatch: " ++ show (Path.toString root)
+                rm = c_inotify_rm_watch (fdFD fd) (fromIntegral wd)
+            void $ throwErrnoIfMinus1 err rm
+            return newMap
+        else return $ Map.insert wd v newMap
+
+-- | Given a 'Config' and list of @paths@ ("/" separated byte arrays) start
+-- monitoring the paths for file system events. Returns a 'Watch' handle which
+-- can then be used to read the event stream or to close the watch.
+--
+-- /Pre-release/
+--
+openWatch :: Config -> NonEmpty Path -> IO Watch
+openWatch cfg paths = do
+    w <- createWatch
+    mapM_ (\root -> addToWatch cfg w (root, Nothing)) $ NonEmpty.toList paths
+    return w
+
+-- | Close a 'Watch' handle.
+--
+-- /Pre-release/
+--
+closeWatch :: Watch -> IO ()
+closeWatch (Watch h _) = hClose h
+
+-------------------------------------------------------------------------------
+-- Raw events read from the watch file handle
+-------------------------------------------------------------------------------
+
+newtype Cookie = Cookie Word32 deriving (Show, Eq)
+
+-- | An Event generated by the file system. Use the accessor functions to
+-- examine the event.
+--
+-- /Pre-release/
+--
+data Event = Event
+   { eventWd :: CInt
+   , eventFlags :: Word32
+   , eventCookie :: Word32
+   , eventRelPath :: Maybe Path
+   , eventMap :: IntMap PathRep
+   }
+
+-- The inotify event struct from the man page/header file:
+--
+--            struct inotify_event {
+--                int      wd;       /* Watch descriptor */
+--                uint32_t mask;     /* Mask describing event */
+--                uint32_t cookie;   /* Unique cookie associating related
+--                                      events (for rename(2)) */
+--                uint32_t len;      /* Size of name field */
+--                char     name[];   /* Optional null-terminated name */
+--            };
+--
+-- XXX We can perhaps use parseD monad instance for fusing with parseMany? Need
+-- to measure the perf.
+--
+readOneEvent :: Config -> Watch -> Parser Word8 IO Event
+readOneEvent cfg  wt@(Watch _ wdMap) = do
+    let headerLen = sizeOf (undefined :: CInt) + 12
+    arr <- PR.takeEQ headerLen (A.createOf headerLen)
+    (ewd, eflags, cookie, pathLen) <- PR.fromEffect $ A.unsafePinnedAsPtr arr readHeader
+    -- XXX need the "initial" in parsers to return a step type so that "take 0"
+    -- can return without an input. otherwise if pathLen is 0 we will keep
+    -- waiting to read one more char before we return this event.
+    wdm <- PR.fromEffect $ readIORef wdMap
+    let prep =
+            case Map.lookup (fromIntegral ewd) wdm of
+                    Just prep0 -> prep0
+                    Nothing ->
+                        error $ "readOneEvent: "
+                                  <> "Unknown watch descriptor: "
+                                  <> show ewd
+    prep1 <-
+        if pathLen /= 0
+        then do
+            -- XXX takeEndBy_ drops the separator so assumes a null
+            -- terminated path, we should use a takeWhile nested inside a
+            -- takeP
+            pth <-
+                PR.fromFold
+                    $ FL.takeEndBy_ (== 0)
+                    $ FL.take pathLen (A.createOf pathLen)
+            let remaining = pathLen - byteLength pth - 1
+            when (remaining /= 0) $ PR.takeEQ remaining FL.drain
+            return $ addSub prep (Path.unsafeFromArray pth)
+        else return $ prep
+    -- Check for "ISDIR" first because it is less likely
+    let isDirCreate = eflags .&. iN_ISDIR /= 0 && eflags .&. iN_CREATE /= 0
+    when (watchRec cfg && isDirCreate)
+        $ PR.fromEffect $ addToWatch cfg wt prep1
+    -- XXX Handle IN_DELETE, IN_DELETE_SELF, IN_MOVE_SELF, IN_MOVED_FROM,
+    -- IN_MOVED_TO
+    -- What if a large dir tree gets moved in to our hierarchy? Do we get a
+    -- single event for the top level dir in this case?
+    return $ Event
+        { eventWd = fromIntegral ewd
+        , eventFlags = eflags
+        , eventCookie = cookie
+        , eventRelPath = getRepSub prep1
+        , eventMap = wdm
+        }
+
+    where
+
+    readHeader (ptr :: Ptr Word8) _ = do
+        let len = sizeOf (undefined :: CInt)
+        ewd <- peek ptr
+        eflags <- peekByteOff ptr len
+        cookie <- peekByteOff ptr (len + 4)
+        pathLen :: Word32 <- peekByteOff ptr (len + 8)
+        return (ewd, eflags, cookie, fromIntegral pathLen)
+
+watchToStream :: Config -> Watch -> Stream IO Event
+watchToStream cfg wt@(Watch handle _) = do
+    -- Do not use too small a buffer. As per inotify man page:
+    --
+    -- The behavior when the buffer given to read(2) is too small to return
+    -- information about the next event depends on the kernel version: in
+    -- kernels before 2.6.21, read(2) returns 0; since kernel 2.6.21, read(2)
+    -- fails with the error EINVAL.  Specifying a buffer of size
+    --
+    --          sizeof(struct inotify_event) + NAME_MAX + 1
+    --
+    -- will be sufficient to read at least one event.
+    S.catRights $ S.parseMany (readOneEvent cfg wt) $ S.unfold FH.reader handle
+
+-- XXX We should not go across the mount points of network file systems or file
+-- systems that are known to not generate any events.
+--
+-- | Start monitoring a list of file system paths for file system events with
+-- the supplied configuration operation over the 'defaultConfig'. The
+-- paths could be files or directories. When recursive mode is set and the
+-- path is a directory, the whole directory tree under it is watched
+-- recursively. Monitoring starts from the current time onwards.
+--
+-- /Non-existing Paths:/ the API fails if a watch is started on a non-exsting
+-- path.
+--
+-- /Performance:/ Note that recursive watch on a large directory tree could be
+-- expensive. When starting a watch, the whole tree must be read and watches
+-- are started on each directory in the tree. The initial time to start the
+-- watch as well as the memory required is proportional to the number of
+-- directories in the tree.
+--
+-- /Bugs:/ When new directories are created under the tree they are added to
+-- the watch on receiving the directory create event. However, the creation of
+-- a dir and adding a watch for it is not atomic.  The implementation takes
+-- care of this and makes sure that watches are added for all directories.
+-- However, In the mean time, the directory may have received more events which
+-- may get lost.  Handling of any such lost events is yet to be implemented.
+--
+-- See the Linux __inotify__ man page for more details.
+--
+-- @
+-- watchwith
+--      ('setFollowSymLinks' True . 'setUnwatchMoved' False)
+--      [Path.fromString "dir"]
+-- @
+--
+-- /Pre-release/
+--
+watchWith :: (Config -> Config) -> NonEmpty Path -> Stream IO Event
+watchWith f paths = S.bracketIO before after (watchToStream cfg)
+
+    where
+
+    cfg = f defaultConfig
+    before = openWatch cfg paths
+    after = closeWatch
+
+-- | Same as 'watchWith' using 'defaultConfig' and recursive mode.
+--
+-- >>> watchRecursive = watchWith (setRecursiveMode True)
+--
+-- See 'watchWith' for pitfalls and bugs when using recursive watch on Linux.
+--
+-- /Pre-release/
+--
+watchRecursive :: NonEmpty Path -> Stream IO Event
+watchRecursive = watchWith (setRecursiveMode True)
+
+-- | Same as 'watchWith' using defaultConfig and non-recursive mode.
+--
+-- >>> watch = watchWith id
+--
+-- /Pre-release/
+--
+watch :: NonEmpty Path -> Stream IO Event
+watch = watchWith id
+
+-------------------------------------------------------------------------------
+-- Examine event stream
+-------------------------------------------------------------------------------
+
+-- XXX Should we return a Maybe here instead of erroring out?
+-- | Get the watch root corresponding to the 'Event'.
+--
+-- Note that if a path was moved after adding to the watch, this will give the
+-- original path and not the new path after moving.
+--
+-- TBD: we can possibly update the watch root on a move self event.
+--
+-- /Pre-release/
+--
+getRoot :: Event -> Path
+getRoot Event{..} =
+    if eventWd >= 1
+    then
+        case Map.lookup (fromIntegral eventWd) eventMap of
+            Just prep -> getRepRoot prep
+            Nothing ->
+                error $ "Bug: getRoot: No path found corresponding to the "
+                    ++ "watch descriptor " ++ show eventWd
+    else error $ "getRoot: ewd = " ++ show eventWd
+
+-- XXX should we use a Maybe here?
+-- | Get the file system object path for which the event is generated, relative
+-- to the watched root. The path is a "/" separated array of bytes.
+--
+-- /Pre-release/
+--
+getRelPath :: Event -> Maybe Path
+getRelPath Event{..} = eventRelPath
+
+-- | Get the absolute file system object path for which the event is generated.
+--
+-- When the watch root is a symlink, the absolute path returned is via the
+-- original symlink and not through the resolved path.
+--
+-- /Pre-release/
+--
+getAbsPath :: Event -> Path
+getAbsPath ev =
+    case getRelPath ev of
+        Just relPath -> Path.join (getRoot ev) relPath
+        Nothing -> getRoot ev
+
+-- XXX should we use a Maybe?
+-- | Cookie is set when a rename occurs. The cookie value can be used to
+-- connect the 'isMovedFrom' and 'isMovedTo' events, if both the events belong
+-- to the same move operation then they will have the same cookie value.
+--
+-- /Pre-release/
+--
+getCookie :: Event -> Cookie
+getCookie Event{..} = Cookie eventCookie
+
+-------------------------------------------------------------------------------
+-- Event types
+-------------------------------------------------------------------------------
+
+getFlag :: Word32 -> Event -> Bool
+getFlag mask Event{..} = eventFlags .&. mask /= 0
+
+-------------------------------------------------------------------------------
+-- Error events
+-------------------------------------------------------------------------------
+
+foreign import capi
+    "sys/inotify.h value IN_Q_OVERFLOW" iN_Q_OVERFLOW :: Word32
+
+-- XXX rename to isQOverflowed or hasOverflowed?
+--
+-- macOS overflow API is more specific, it tells which paths have lost the
+-- events due to overflow.
+--
+-- | Event queue overflowed (WD is invalid for this event) and we may have lost
+-- some events..  The user application must scan everything under the watched
+-- paths to know the current state.
+--
+-- /Pre-release/
+--
+isEventsLost :: Event -> Bool
+isEventsLost = getFlag iN_Q_OVERFLOW
+
+-------------------------------------------------------------------------------
+-- Events affecting the watched path only
+-------------------------------------------------------------------------------
+
+foreign import capi
+    "sys/inotify.h value IN_IGNORED" iN_IGNORED :: Word32
+
+-- Compare with isRootChanged on macOS. isRootChanged includes all these cases.
+--
+-- | A path was removed from the watch explicitly using 'removeFromWatch' or
+-- automatically (file was deleted, or filesystem was unmounted).
+--
+-- Note that in recursive watch mode all the subdirectories are watch roots,
+-- therefore, they will all generate this event.
+--
+-- /Occurs only for a watched path/
+--
+-- /Pre-release/
+--
+isRootUnwatched :: Event -> Bool
+isRootUnwatched = getFlag iN_IGNORED
+
+-- | Watched file/directory was itself deleted.  (This event also occurs if an
+-- object is moved to another filesystem, since mv(1) in effect copies the file
+-- to the other filesystem and then deletes it from the original filesystem.)
+-- In addition, an 'isRootUnwatched' event will subsequently be generated
+-- for the watch descriptor.
+--
+-- Note that in recursive watch mode all the subdirectories are watch roots,
+-- therefore, they will all generate this event.
+--
+-- /Occurs only for a watched path/
+--
+-- /Pre-release/
+--
+isRootDeleted :: Event -> Bool
+isRootDeleted = getFlag iN_DELETE_SELF
+
+-- | Watched file/directory was itself moved within the file system.
+--
+-- Note that in recursive watch mode all the subdirectories are watch roots,
+-- therefore, they will all generate this event.
+--
+-- /Occurs only for a watched path/
+--
+-- /Pre-release/
+--
+isRootMoved :: Event -> Bool
+isRootMoved = getFlag iN_MOVE_SELF
+
+foreign import capi
+    "sys/inotify.h value IN_UNMOUNT" iN_UNMOUNT :: Word32
+
+-- | Filesystem containing watched object was unmounted.  In addition, an
+-- 'isRootUnwatched' event will subsequently be generated for the watch
+-- descriptor.
+--
+-- /Occurs only for a watched path/
+--
+-- /Pre-release/
+--
+isRootUnmounted :: Event -> Bool
+isRootUnmounted = getFlag iN_UNMOUNT
+
+-- | Determine whether the event indicates a change of path of the monitored
+-- object itself. Note that the object may become unreachable or deleted after
+-- a change of path.
+--
+-- /Occurs only for a watched path/
+--
+-- /Pre-release/
+--
+isRootPathEvent :: Event -> Bool
+isRootPathEvent = getFlag (iN_DELETE_SELF .|. iN_MOVE_SELF .|. iN_UNMOUNT)
+
+-------------------------------------------------------------------------------
+-- Metadata change Events
+-------------------------------------------------------------------------------
+
+-- macOS has multiple APIs for metadata change for different metadata.
+--
+-- | Determine whether the event indicates inode metadata change for an object
+-- contained within the monitored path.
+--
+-- Metadata change may include, permissions (e.g., chmod(2)), timestamps
+-- (e.g., utimensat(2)), extended attributes (setxattr(2)), link count (since
+-- Linux 2.6.25; e.g., for the target of link(2) and for unlink(2)), and
+-- user/group ID (e.g., chown(2)).
+--
+-- /Can occur for watched path or a file inside it/
+--
+-- /Pre-release/
+--
+isAttrsModified :: Event -> Bool
+isAttrsModified = getFlag iN_ATTRIB
+
+-------------------------------------------------------------------------------
+-- Access
+-------------------------------------------------------------------------------
+
+-- | File was accessed (e.g. read, execve).
+--
+-- /Occurs only for a file inside the watched directory/
+--
+-- /Pre-release/
+--
+isAccessed :: Event -> Bool
+isAccessed = getFlag iN_ACCESS
+
+-- | File or directory was opened.
+--
+-- /Occurs only for a file inside the watched directory/
+--
+-- /Pre-release/
+--
+isOpened :: Event -> Bool
+isOpened = getFlag iN_OPEN
+
+-- | File opened for writing was closed.
+--
+-- /Occurs only for a file inside the watched directory/
+--
+-- /Pre-release/
+--
+isWriteClosed :: Event -> Bool
+isWriteClosed = getFlag iN_CLOSE_WRITE
+
+-- XXX what if it was opened for append? Does NOWRITE mean all cases where the
+-- mode was not write? A dir open comes in this category?
+--
+-- | File or directory opened for read but not write was closed.
+--
+-- /Can occur for watched path or a file inside it/
+--
+-- /Pre-release/
+--
+isNonWriteClosed :: Event -> Bool
+isNonWriteClosed = getFlag iN_CLOSE_NOWRITE
+
+-------------------------------------------------------------------------------
+-- CRUD Events
+-------------------------------------------------------------------------------
+
+-- On macOS this is not generated on hard linking but on Linux it is.
+--
+-- | File/directory created in watched directory (e.g., open(2) O_CREAT,
+-- mkdir(2), link(2), symlink(2), bind(2) on a UNIX domain socket).
+--
+-- /Occurs only for an object inside the watched directory/
+--
+-- /Pre-release/
+--
+isCreated :: Event -> Bool
+isCreated = getFlag iN_CREATE
+
+-- | File/directory deleted from watched directory.
+--
+-- /Occurs only for an object inside the watched directory/
+--
+-- /Pre-release/
+--
+isDeleted :: Event -> Bool
+isDeleted = getFlag iN_DELETE
+
+-- XXX what if an object is moved in from outside or moved out of the monitored
+-- dir?
+--
+-- | Generated for the original path when an object is moved from under a
+-- monitored directory.
+--
+-- /Occurs only for an object inside the watched directory/
+--
+-- /Pre-release/
+--
+isMovedFrom :: Event -> Bool
+isMovedFrom = getFlag iN_MOVED_FROM
+
+-- | Generated for the new path when an object is moved under a monitored
+-- directory.
+--
+-- /Occurs only for an object inside the watched directory/
+--
+-- /Pre-release/
+--
+isMovedTo :: Event -> Bool
+isMovedTo = getFlag iN_MOVED_TO
+
+-- | Generated for a path that is moved from or moved to the monitored
+-- directory.
+--
+-- >>> isMoved ev = isMovedFrom ev || isMovedTo ev
+--
+-- /Occurs only for an object inside the watched directory/
+--
+-- /Pre-release/
+--
+isMoved :: Event -> Bool
+isMoved ev = isMovedFrom ev || isMovedTo ev
+
+-- | Determine whether the event indicates modification of an object within the
+-- monitored path. This event is generated only for files and not directories.
+--
+-- /Occurs only for an object inside the watched directory/
+--
+-- /Pre-release/
+--
+isModified :: Event -> Bool
+isModified = getFlag iN_MODIFY
+
+-------------------------------------------------------------------------------
+-- Information about path type (applicable only when 'setFileEvents' is 'True')
+-------------------------------------------------------------------------------
+
+foreign import capi
+    "sys/inotify.h value IN_ISDIR" iN_ISDIR :: Word32
+
+-- | Determine whether the event is for a directory path.
+--
+-- /Pre-release/
+--
+isDir :: Event -> Bool
+isDir = getFlag iN_ISDIR
+
+-------------------------------------------------------------------------------
+-- Debugging
+-------------------------------------------------------------------------------
+
+-- | Convert an 'Event' record to a String representation.
+showEvent :: Event -> String
+showEvent ev@Event{..} =
+       "--------------------------"
+    ++ "\nWd = " ++ show eventWd
+    ++ "\nRoot = " ++ show (Path.toString $ getRoot ev)
+    ++ "\nPath = " ++ maybe "" (show . Path.toString) (getRelPath ev)
+    ++ "\nCookie = " ++ show (getCookie ev)
+    ++ "\nFlags " ++ show eventFlags
+
+    ++ showev isEventsLost "Overflow"
+
+    ++ showev isRootUnwatched "RootUnwatched"
+    ++ showev isRootDeleted "RootDeleted"
+    ++ showev isRootMoved "RootMoved"
+    ++ showev isRootUnmounted "RootUnmounted"
+
+    ++ showev isAttrsModified "AttrsModified"
+
+    ++ showev isAccessed "Accessed"
+    ++ showev isOpened "Opened"
+    ++ showev isWriteClosed "WriteClosed"
+    ++ showev isNonWriteClosed "NonWriteClosed"
+
+    ++ showev isCreated "Created"
+    ++ showev isDeleted "Deleted"
+    ++ showev isModified "Modified"
+    ++ showev isMovedFrom "MovedFrom"
+    ++ showev isMovedTo "MovedTo"
+
+    ++ showev isDir "Dir"
+    ++ "\n"
+
+        where showev f str = if f ev then "\n" ++ str else ""
+#else
+#warning "Disabling module Streamly.Internal.FS.Event.Linux. Does not support kernels older than 2.6.36."
+module Streamly.Internal.FS.Event.Linux () where
+#endif
diff --git a/src/Streamly/Internal/FS/Event/Windows.hs b/src/Streamly/Internal/FS/Event/Windows.hs
new file mode 100644
--- /dev/null
+++ b/src/Streamly/Internal/FS/Event/Windows.hs
@@ -0,0 +1,618 @@
+-- Some code snippets are adapted from the fsnotify package.
+-- http://hackage.haskell.org/package/fsnotify-0.3.0.1/
+--
+-- |
+-- Module      : Streamly.Internal.FS.Event.Windows
+-- Copyright   : (c) 2020 Composewell Technologies
+--               (c) 2012, Mark Dittmer
+-- License     : BSD-3-Clause
+-- Maintainer  : streamly@composewell.com
+-- Stability   : pre-release
+-- Portability : GHC
+--
+-- =Overview
+--
+-- Use 'watchRecursive'or 'watch' with a list of file system dir paths you
+-- want to watch as argument. It returns a stream of 'Event' representing the
+-- file system events occurring under the watched paths.
+--
+-- @
+-- {-\# LANGUAGE MagicHash #-}
+-- Stream.mapM_ (putStrLn . 'showEvent') $ 'watchRecursive' [Path.fromString "path"]
+-- @
+--
+-- 'Event' is an opaque type. Accessor functions (e.g. 'showEvent' above)
+-- provided in this module are used to determine the attributes of the event.
+--
+-- =Design notes
+--
+-- For Windows reference documentation see:
+--
+-- * <https://docs.microsoft.com/en-us/windows/win32/api/winnt/ns-winnt-file_notify_information file notify information>
+-- * <https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-readdirectorychangesw read directory changes>
+--
+-- We try to keep the macOS\/Linux/Windows event handling APIs and defaults
+-- semantically and syntactically as close as possible.
+--
+-- =Availability
+--
+-- As per the Windows reference docs, the fs event notification API is
+-- available in:
+--
+-- * Minimum supported client: Windows XP [desktop apps | UWP apps]
+-- * Minimum supported server: Windows Server 2003 [desktop apps | UWP apps
+
+module Streamly.Internal.FS.Event.Windows
+    (
+    -- * Subscribing to events
+
+    -- ** Default configuration
+      Config
+    , defaultConfig
+
+    -- ** Watch Behavior
+    , setRecursiveMode
+
+    -- ** Events of Interest
+    , setFileNameEvents
+    , setDirNameEvents
+    , setAttrsModified
+    , setSecurityModified
+    , setSizeModified
+    , setLastWriteTimeModified
+    , setAllEvents
+
+    -- ** Watch APIs
+    , watch
+    , watchRecursive
+    , watchWith
+
+    -- * Handling Events
+    , Event(..)
+    , getRoot
+    , getRelPath
+    , getAbsPath
+
+    -- ** Item CRUD events
+    , isCreated
+    , isDeleted
+    , isModified
+    , isMoved
+    , isMovedFrom
+    , isMovedTo
+
+    -- ** Exception Conditions
+    , isEventsLost
+
+    -- * Debugging
+    , showEvent
+    )
+where
+
+import Data.Bits ((.|.), (.&.), complement)
+import Data.List.NonEmpty (NonEmpty)
+import Foreign.Marshal.Alloc (alloca, allocaBytes)
+import Foreign.Storable (peekByteOff)
+import Foreign.Ptr (Ptr, FunPtr, castPtr, nullPtr, nullFunPtr, plusPtr)
+import System.Win32.File
+    ( FileNotificationFlag
+    , LPOVERLAPPED
+    , closeHandle
+    , createFile
+    , fILE_FLAG_BACKUP_SEMANTICS
+    , fILE_LIST_DIRECTORY
+    , fILE_NOTIFY_CHANGE_FILE_NAME
+    , fILE_NOTIFY_CHANGE_DIR_NAME
+    , fILE_NOTIFY_CHANGE_ATTRIBUTES
+    , fILE_NOTIFY_CHANGE_SIZE
+    , fILE_NOTIFY_CHANGE_LAST_WRITE
+    , fILE_NOTIFY_CHANGE_SECURITY
+    , fILE_SHARE_READ
+    , fILE_SHARE_WRITE
+    , oPEN_EXISTING
+    )
+import System.Win32.Types (BOOL, DWORD, HANDLE, LPVOID, LPDWORD, failIfFalse_)
+
+import Streamly.Data.Stream (Stream)
+import Streamly.Data.Stream.Prelude (eager)
+import Streamly.Internal.FileSystem.Path (Path)
+
+import qualified Data.List.NonEmpty as NonEmpty
+import qualified Streamly.Data.Fold as Fold
+import qualified Streamly.Data.Stream as S
+import qualified Streamly.Data.Stream.Prelude as S
+import qualified Streamly.Internal.Data.Array as Array
+import qualified Streamly.Internal.FileSystem.Path as Path
+
+-- | Watch configuration, used to specify the events of interest and the
+-- behavior of the watch.
+--
+-- /Pre-release/
+--
+data Config = Config
+    { watchRec :: BOOL
+    , createFlags :: DWORD
+    }
+
+-------------------------------------------------------------------------------
+-- Boolean settings
+-------------------------------------------------------------------------------
+
+setFlag :: DWORD -> Bool -> Config -> Config
+setFlag mask status cfg@Config{..} =
+    let flags =
+            if status
+            then createFlags .|. mask
+            else createFlags .&. complement mask
+    in cfg {createFlags = flags}
+
+-- | Set watch event on directory recursively.
+--
+-- /default: False/
+--
+-- /Pre-release/
+--
+setRecursiveMode :: Bool -> Config -> Config
+setRecursiveMode recursive cfg@Config{} = cfg {watchRec = recursive}
+
+-- | Generate notify events on file create, rename or delete.
+--
+-- From Windows API documentation: Any file name change in the watched
+-- directory or subtree causes a change notification wait operation to return.
+-- Changes include renaming, creating, or deleting a file.
+--
+-- /default: True/
+--
+-- /Pre-release/
+--
+setFileNameEvents :: Bool -> Config -> Config
+setFileNameEvents = setFlag fILE_NOTIFY_CHANGE_FILE_NAME
+
+-- | Generate notify events on directory create, rename or delete.
+--
+-- From Windows API documentaiton: Any directory-name change in the watched
+-- directory or subtree causes a change notification wait operation to return.
+-- Changes include creating or deleting a directory.
+--
+-- /default: True/
+--
+-- /Pre-release/
+--
+setDirNameEvents :: Bool -> Config -> Config
+setDirNameEvents = setFlag fILE_NOTIFY_CHANGE_DIR_NAME
+
+-- | Generate an 'isModified' event on any attribute change in the watched
+-- directory or subtree.
+--
+-- /default: False/
+--
+-- /Pre-release/
+--
+setAttrsModified :: Bool -> Config -> Config
+setAttrsModified = setFlag fILE_NOTIFY_CHANGE_ATTRIBUTES
+
+-- | Generate an 'isModified' event when the file size is changed.
+--
+-- From Windows API documentation: Any file-size change in the watched
+-- directory or subtree causes a change notification wait operation to return.
+-- The operating system detects a change in file size only when the file is
+-- written to the disk. For operating systems that use extensive caching,
+-- detection occurs only when the cache is sufficiently flushed.
+--
+-- /default: False/
+--
+-- /Pre-release/
+--
+setSizeModified :: Bool -> Config -> Config
+setSizeModified = setFlag fILE_NOTIFY_CHANGE_SIZE
+
+-- | Generate an 'isModified' event when the last write timestamp of the file
+-- inode is changed.
+--
+-- From Windows API documentation: Any change to the last write-time of files
+-- in the watched directory or subtree causes a change notification wait
+-- operation to return. The operating system detects a change to the last
+-- write-time only when the file is written to the disk. For operating systems
+-- that use extensive caching, detection occurs only when the cache is
+-- sufficiently flushed.
+--
+-- /default: False/
+--
+-- /Pre-release/
+--
+setLastWriteTimeModified :: Bool -> Config -> Config
+setLastWriteTimeModified = setFlag fILE_NOTIFY_CHANGE_LAST_WRITE
+
+-- | Generate an 'isModified' event when any security-descriptor change occurs
+-- in the watched directory or subtree.
+--
+-- /default: False/
+--
+-- /Pre-release/
+--
+setSecurityModified :: Bool -> Config -> Config
+setSecurityModified = setFlag fILE_NOTIFY_CHANGE_SECURITY
+
+-- | Set all tunable events 'True' or 'False'. Equivalent to setting:
+--
+-- * setFileNameEvents
+-- * setDirNameEvents
+-- * setAttrsModified
+-- * setSizeModified
+-- * setLastWriteTimeModified
+-- * setSecurityModified
+--
+-- /Pre-release/
+--
+setAllEvents :: Bool -> Config -> Config
+setAllEvents s =
+      setFileNameEvents s
+    . setDirNameEvents s
+    . setAttrsModified s
+    . setSizeModified s
+    . setLastWriteTimeModified s
+    . setSecurityModified s
+
+-- | The tunable events that are enabled by default are:
+--
+-- * setFileNameEvents True
+-- * setDirNameEvents True
+-- * setSizeModified True
+-- * setLastWriteTimeModified True
+--
+-- /Pre-release/
+--
+defaultConfig :: Config
+defaultConfig =
+      setFileNameEvents True
+    $ setDirNameEvents True
+    $ setSizeModified True
+    $ setLastWriteTimeModified True
+    $ Config {watchRec = False, createFlags = 0}
+
+getConfigFlag :: Config -> DWORD
+getConfigFlag Config{..} = createFlags
+
+getConfigRecMode :: Config -> BOOL
+getConfigRecMode Config{..} = watchRec
+
+data Event = Event
+    { eventFlags :: DWORD
+    , eventRelPath :: Path
+    , eventRootPath :: Path
+    , totalBytes :: DWORD
+    }
+
+-- For reference documentation see:
+--
+-- See https://docs.microsoft.com/en-us/windows/win32/api/winnt/ns-winnt-file_notify_information
+data FILE_NOTIFY_INFORMATION = FILE_NOTIFY_INFORMATION
+    { fniNextEntryOffset :: DWORD
+    , fniAction :: DWORD
+    , fniFileName :: Path
+    }
+
+type LPOVERLAPPED_COMPLETION_ROUTINE =
+    FunPtr ((DWORD, DWORD, LPOVERLAPPED) -> IO ())
+
+-- | A handle for a watch.
+getWatchHandle :: Path -> IO (HANDLE, Path)
+getWatchHandle dir = do
+    let dirStr = Path.toString dir
+    h <- createFile dirStr
+        -- Access mode
+        fILE_LIST_DIRECTORY
+        -- Share mode
+        (fILE_SHARE_READ .|. fILE_SHARE_WRITE)
+        -- Security attributes
+        Nothing
+        -- Create mode, we want to look at an existing directory
+        oPEN_EXISTING
+        -- File attribute, NOT using OVERLAPPED since we work synchronously
+        fILE_FLAG_BACKUP_SEMANTICS
+        -- No template file
+        Nothing
+    return (h, dir)
+
+-- For reference documentation see:
+--
+-- See https://docs.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-readdirectorychangesw
+-- Note that this API uses UTF-16 for file system paths:
+-- 1. https://docs.microsoft.com/en-us/windows/win32/intl/unicode-in-the-windows-api
+-- 2. https://docs.microsoft.com/en-us/windows/win32/intl/unicode
+foreign import ccall safe
+    "windows.h ReadDirectoryChangesW" c_ReadDirectoryChangesW ::
+           HANDLE
+        -> LPVOID
+        -> DWORD
+        -> BOOL
+        -> DWORD
+        -> LPDWORD
+        -> LPOVERLAPPED
+        -> LPOVERLAPPED_COMPLETION_ROUTINE
+        -> IO BOOL
+
+readDirectoryChangesW ::
+       HANDLE
+    -> Ptr FILE_NOTIFY_INFORMATION
+    -> DWORD
+    -> BOOL
+    -> FileNotificationFlag
+    -> LPDWORD
+    -> IO ()
+readDirectoryChangesW h buf bufSize wst f br =
+    let res = c_ReadDirectoryChangesW
+                    h (castPtr buf) bufSize wst f br nullPtr nullFunPtr
+     in failIfFalse_ "ReadDirectoryChangesW" res
+
+peekFNI :: Ptr FILE_NOTIFY_INFORMATION -> IO FILE_NOTIFY_INFORMATION
+peekFNI buf = do
+    neof <- peekByteOff buf 0
+    acti <- peekByteOff buf 4
+    (fnle :: DWORD) <- peekByteOff buf 8
+    fnam0 <- Array.fromPtrN (fromIntegral fnle) (buf `plusPtr` 12)
+    fnam <- Path.fromArray (Array.unsafeCast fnam0)
+    return $ FILE_NOTIFY_INFORMATION neof acti fnam
+
+readChangeEvents ::
+    Ptr FILE_NOTIFY_INFORMATION -> Path -> DWORD -> IO [Event]
+readChangeEvents pfni root bytesRet = do
+    fni <- peekFNI pfni
+    let entry = Event
+            { eventFlags = fniAction fni
+            , eventRelPath = fniFileName fni
+            , eventRootPath = root
+            , totalBytes = bytesRet
+            }
+        nioff = fromEnum $ fniNextEntryOffset fni
+    entries <-
+        if nioff == 0
+        then return []
+        else readChangeEvents (pfni `plusPtr` nioff) root bytesRet
+    return $ entry : entries
+
+readDirectoryChanges ::
+    Path -> HANDLE -> Bool -> FileNotificationFlag -> IO [Event]
+readDirectoryChanges root h wst mask = do
+    let maxBuf = 63 * 1024
+    allocaBytes maxBuf $ \buffer -> do
+        alloca $ \bret -> do
+            readDirectoryChangesW h buffer (toEnum maxBuf) wst mask bret
+            bytesRet <- peekByteOff bret 0
+            readChangeEvents buffer root bytesRet
+
+-- XXX Try to get these from windows header files
+type FileAction = DWORD
+
+fILE_ACTION_ADDED             :: FileAction
+fILE_ACTION_ADDED             =  1
+
+fILE_ACTION_REMOVED           :: FileAction
+fILE_ACTION_REMOVED           =  2
+
+fILE_ACTION_MODIFIED          :: FileAction
+fILE_ACTION_MODIFIED          =  3
+
+fILE_ACTION_RENAMED_OLD_NAME  :: FileAction
+fILE_ACTION_RENAMED_OLD_NAME  =  4
+
+fILE_ACTION_RENAMED_NEW_NAME  :: FileAction
+fILE_ACTION_RENAMED_NEW_NAME  =  5
+
+eventStreamAggr :: (HANDLE, Path, Config) -> Stream IO Event
+eventStreamAggr (handle, rootPath, cfg) =  do
+    let recMode = getConfigRecMode cfg
+        flagMasks = getConfigFlag cfg
+        repeatM = S.sequence . S.repeat
+    S.concatMap S.fromList $ repeatM
+        $ readDirectoryChanges rootPath handle recMode flagMasks
+
+pathsToHandles ::
+    NonEmpty Path -> Config -> Stream IO (HANDLE, Path, Config)
+pathsToHandles paths cfg = do
+    let pathStream = S.fromList (NonEmpty.toList paths)
+        st2 = S.mapM getWatchHandle pathStream
+    fmap (\(h, f) -> (h, f, cfg)) st2
+
+-------------------------------------------------------------------------------
+-- Utilities
+-------------------------------------------------------------------------------
+
+-- | Close a Directory handle.
+--
+closePathHandleStream :: Stream IO (HANDLE, Path, Config) -> IO ()
+closePathHandleStream =
+    let f (h, _, _) = closeHandle h
+        in S.fold (Fold.drainMapM f)
+
+-- XXX
+-- Remove the encoding requirement of paths? It can be encoding agnostic
+-- "\" separated bytes, the application can decide what encoding to use.
+-- Instead of always using widechar (-W) APIs can we call the underlying APIs
+-- based on the configured code page?
+-- https://docs.microsoft.com/en-us/windows/uwp/design/globalizing/use-utf8-code-page
+--
+-- | Start monitoring a list of directory paths for file system events with the
+-- supplied configuration modifier operation over the' defaultConfig'. The
+-- paths could be directories or symbolic links to directories.
+--
+-- When recursive mode is True, the whole directory tree under the path is
+-- watched recursively.  When recursive mode is False, only the files and
+-- directories directly under the watched directory are monitored, contents of
+-- subdirectories are not monitored.  Monitoring starts from the current time
+-- onwards.
+--
+-- /Symbolic Links:/ If the pathname to be watched is a symbolic link then
+-- watch the target of the symbolic link instead of the symbolic link itself.
+-- Note that the path location in the events is through the original symbolic
+-- link path rather than the resolved path.
+--
+-- @
+-- watchWith
+--  ('setAttrsModified' True . 'setLastWriteTimeModified' False)
+--  [Path.fromString "dir"]
+-- @
+--
+-- /Pre-release/
+--
+watchWith :: (Config -> Config) -> NonEmpty Path -> Stream IO Event
+watchWith f paths =
+    S.bracketIO before after (S.parConcatMap (eager True) eventStreamAggr)
+
+    where
+
+    before = return $ pathsToHandles paths $ f defaultConfig
+    after = closePathHandleStream
+
+-- | Same as 'watchWith' using 'defaultConfig' and recursive mode.
+--
+-- >>> watchRecursive = watchWith (setRecursiveMode True)
+--
+-- /Pre-release/
+--
+watchRecursive :: NonEmpty Path -> Stream IO Event
+watchRecursive = watchWith (setRecursiveMode True)
+
+-- | Same as 'watchWith' using defaultConfig and non-recursive mode.
+--
+-- >>> watch = watchWith id
+--
+-- /Pre-release/
+--
+watch :: NonEmpty Path -> Stream IO Event
+watch = watchWith id
+
+getFlag :: DWORD -> Event -> Bool
+getFlag mask Event{..} = eventFlags == mask
+
+-- | Get the file system object path for which the event is generated, relative
+-- to the watched root.
+--
+-- /Pre-release/
+--
+getRelPath :: Event -> Path
+getRelPath Event{..} = eventRelPath
+
+-- | Get the watch root directory to which this event belongs.
+--
+-- /Pre-release/
+--
+getRoot :: Event -> Path
+getRoot Event{..} = eventRootPath
+
+-- | Get the absolute file system object path for which the event is generated.
+--
+-- When the watch root is a symlink, the absolute path returned is via the
+-- original symlink and not through the resolved path.
+--
+-- /Pre-release/
+--
+getAbsPath :: Event -> Path
+getAbsPath ev = Path.join (getRoot ev) (getRelPath ev)
+
+-- XXX need to document the exact semantics of these.
+--
+-- | This event is generated when a file or directory is created in a watched
+-- directory or directory tree when in recursive watch mode.  Creating a hard
+-- link also generates this event.
+--
+-- /Occurs when either 'setFileNameEvents' or 'setDirNameEvents' is enabled/
+--
+-- /Pre-release/
+--
+isCreated :: Event -> Bool
+isCreated = getFlag fILE_ACTION_ADDED
+
+-- | This event is generated when a file or directory is deleted from the
+-- watched directory or directory tree when in recursive mode. This event is
+-- generated even when a hard link is deleted.
+--
+-- /Occurs when either 'setFileNameEvents' or 'setDirNameEvents' is enabled/
+--
+-- /Pre-release/
+--
+isDeleted :: Event -> Bool
+isDeleted = getFlag fILE_ACTION_REMOVED
+
+-- | Generated for the original path when an object is moved from under a
+-- monitored directory.
+--
+-- /Occurs when either 'setFileNameEvents' or 'setDirNameEvents' is enabled/
+--
+-- /Pre-release/
+--
+isMovedFrom :: Event -> Bool
+isMovedFrom = getFlag fILE_ACTION_RENAMED_OLD_NAME
+
+-- | Generated for the new path when an object is moved under a monitored
+-- directory.
+--
+-- /Occurs when either 'setFileNameEvents' or 'setDirNameEvents' is enabled/
+--
+-- /Pre-release/
+--
+isMovedTo :: Event -> Bool
+isMovedTo = getFlag fILE_ACTION_RENAMED_NEW_NAME
+
+-- | Generated for a path that is moved from or moved to the monitored
+-- directory.
+--
+-- >>> isMoved ev = isMovedFrom ev || isMovedTo ev
+--
+-- /Occurs when either 'setFileNameEvents' or 'setDirNameEvents' is enabled/
+-- /Occurs only for an object inside the watched directory/
+--
+-- /Pre-release/
+--
+isMoved :: Event -> Bool
+isMoved ev = isMovedFrom ev || isMovedTo ev
+
+-- XXX This event is generated only for files and not directories?
+--
+-- | This event occurs when a file or directory contents, timestamps or
+-- attributes are modified.  Since it can occur on multiple changes, you may
+-- have to check the attributes to know what exactly changed when multiple type
+-- of modified events are enabled.
+--
+-- In non-recursive mode this event does not occur for directories.  In
+-- recursive mode this event occurs for the parent directory if a file or
+-- directory inside it is created or renamed.
+--
+-- /Occurs when one of the @set*Modified@ events is enabled/
+--
+-- /Pre-release/
+--
+isModified :: Event -> Bool
+isModified = getFlag fILE_ACTION_MODIFIED
+
+-- | If the kernel event buffer overflows, entire contents of the buffer are
+-- discarded, therefore, events are lost.  The user application must scan
+-- everything under the watched paths to know the current state of the file
+-- system tree.
+--
+-- /Pre-release/
+--
+isEventsLost :: Event -> Bool
+isEventsLost Event{..} = totalBytes == 0
+
+-------------------------------------------------------------------------------
+-- Debugging
+-------------------------------------------------------------------------------
+
+-- | Convert an 'Event' record to a String representation.
+showEvent :: Event -> String
+showEvent ev@Event{..} =
+        "--------------------------"
+    ++ "\nRoot = " ++ Path.toString (getRoot ev)
+    ++ "\nPath = " ++ Path.toString (getRelPath ev)
+    ++ "\ngetAbsPath = " ++ Path.toString (getAbsPath ev)
+    ++ "\nFlags " ++ show eventFlags
+    ++ showev isEventsLost "Overflow"
+    ++ showev isCreated "Created"
+    ++ showev isDeleted "Deleted"
+    ++ showev isModified "Modified"
+    ++ showev isMovedFrom "MovedFrom"
+    ++ showev isMovedTo "MovedTo"
+    ++ "\n"
+
+    where showev f str = if f ev then "\n" ++ str else ""
diff --git a/src/config.h.in b/src/config.h.in
new file mode 100644
--- /dev/null
+++ b/src/config.h.in
@@ -0,0 +1,43 @@
+/* src/config.h.in.  Generated from configure.ac by autoheader.  */
+
+/* Define to 1 if you have the declaration of `IN_EXCL_UNLINK', and to 0 if
+   you don't. */
+#undef HAVE_DECL_IN_EXCL_UNLINK
+
+/* Define to 1 if you have the declaration of `IN_MASK_CREATE', and to 0 if
+   you don't. */
+#undef HAVE_DECL_IN_MASK_CREATE
+
+/* Define to 1 if you have the declaration of
+   `kFSEventStreamCreateFlagFileEvents', and to 0 if you don't. */
+#undef HAVE_DECL_KFSEVENTSTREAMCREATEFLAGFILEEVENTS
+
+/* Define to 1 if you have the declaration of
+   `kFSEventStreamCreateFlagFullHistory', and to 0 if you don't. */
+#undef HAVE_DECL_KFSEVENTSTREAMCREATEFLAGFULLHISTORY
+
+/* Define to 1 if you have the declaration of
+   `kFSEventStreamEventFlagItemCloned', and to 0 if you don't. */
+#undef HAVE_DECL_KFSEVENTSTREAMEVENTFLAGITEMCLONED
+
+/* Define to 1 if you have the declaration of
+   `kFSEventStreamEventFlagItemIsHardlink', and to 0 if you don't. */
+#undef HAVE_DECL_KFSEVENTSTREAMEVENTFLAGITEMISHARDLINK
+
+/* Define to the address where bug reports for this package should be sent. */
+#undef PACKAGE_BUGREPORT
+
+/* Define to the full name of this package. */
+#undef PACKAGE_NAME
+
+/* Define to the full name and version of this package. */
+#undef PACKAGE_STRING
+
+/* Define to the one symbol short name of this package. */
+#undef PACKAGE_TARNAME
+
+/* Define to the home page for this package. */
+#undef PACKAGE_URL
+
+/* Define to the version of this package. */
+#undef PACKAGE_VERSION
diff --git a/streamly-fsevents.cabal b/streamly-fsevents.cabal
new file mode 100644
--- /dev/null
+++ b/streamly-fsevents.cabal
@@ -0,0 +1,288 @@
+cabal-version:      2.2
+name:               streamly-fsevents
+version:            0.1.0
+synopsis:           File system event notification API
+description:        File system event notification API
+
+homepage:            https://streamly.composewell.com
+bug-reports:         https://github.com/composewell/streamly/issues
+license:             BSD-3-Clause
+license-file:        LICENSE
+tested-with:         GHC==8.6.5
+                   , GHC==8.8.4
+                   , GHC==8.10.7
+                   , GHC==9.0.2
+                   , GHC==9.2.8
+                   , GHC==9.4.7
+                   , GHC==9.6.3
+                   , GHC==9.8.1
+author:              Composewell Technologies
+maintainer:          streamly@composewell.com
+copyright:           2017 Composewell Technologies
+category:
+    Streamly, Concurrency, Streaming, Dataflow, Pipes, Reactivity, List,
+    Logic, Non-determinism, Parsing, Array, Time, Unicode, Filesystem,
+    Network
+stability:           Stable
+build-type:          Configure
+
+extra-source-files:
+    README.md
+    configure
+    configure.ac
+    src/Streamly/Internal/FS/Event/Darwin.h
+    src/config.h.in
+
+extra-doc-files:
+    Changelog.md
+
+extra-tmp-files:
+    config.log
+    config.status
+    autom4te.cache
+    src/config.h
+
+source-repository head
+    type: git
+    location: https://github.com/composewell/streamly
+
+flag fusion-plugin
+  description: Enable fusion plugin
+  manual: True
+  default: False
+
+flag internal-dev
+  description: Development build
+  manual: True
+  default: False
+
+flag opt
+  description: off=GHC default, on=-O2
+  manual: True
+  default: True
+
+flag limit-build-mem
+  description: Limits memory when building
+  manual: True
+  default: False
+
+-------------------------------------------------------------------------------
+-- Common stanzas
+-------------------------------------------------------------------------------
+
+common compile-options
+    default-language: Haskell2010
+
+    if os(darwin)
+      cpp-options:    -DCABAL_OS_DARWIN
+
+    if os(linux)
+      cpp-options:    -DCABAL_OS_LINUX
+
+    if os(windows)
+      cpp-options:    -DCABAL_OS_WINDOWS
+
+    if flag(internal-dev)
+      cpp-options:    -DDEVBUILD
+
+    ghc-options:    -Weverything
+                    -Wno-implicit-prelude
+                    -Wno-missing-deriving-strategies
+                    -Wno-missing-exported-signatures
+                    -Wno-missing-import-lists
+                    -Wno-missing-local-signatures
+                    -Wno-missing-safe-haskell-mode
+                    -Wno-missed-specialisations
+                    -Wno-all-missed-specialisations
+                    -Wno-monomorphism-restriction
+                    -Wno-prepositive-qualified-module
+                    -Wno-unsafe
+                    -Rghc-timing
+
+    if impl(ghc >= 9.2)
+      ghc-options:
+        -Wno-missing-kind-signatures
+        -Wno-redundant-bang-patterns
+        -Wno-operator-whitespace
+
+    if impl(ghc >= 9.8)
+      ghc-options:
+        -Wno-missing-role-annotations
+
+    if flag(internal-dev)
+      ghc-options:    -Wmissed-specialisations
+                      -Wall-missed-specialisations
+
+    if flag(limit-build-mem)
+        ghc-options: +RTS -M1000M -RTS
+
+common default-extensions
+    default-extensions:
+        BangPatterns
+        ConstraintKinds
+        DeriveDataTypeable
+        DeriveGeneric
+        DeriveTraversable
+        ExistentialQuantification
+        FlexibleContexts
+        FlexibleInstances
+        GeneralizedNewtypeDeriving
+        InstanceSigs
+        KindSignatures
+        MultiParamTypeClasses
+        RankNTypes
+        ScopedTypeVariables
+        TupleSections
+        TypeApplications
+        TypeOperators
+
+        -- Not GHC2021
+        CApiFFI
+        CPP
+        LambdaCase
+        MagicHash
+        RecordWildCards
+
+        -- TypeFamilies -- required by IsHashMap type class
+        -- MonoLocalBinds, enabled by TypeFamilies, causes performance
+        -- regressions. Disable it. This must come after TypeFamilies,
+        -- otherwise TypeFamilies will enable it again.
+        -- NoMonoLocalBinds
+
+        -- UndecidableInstances -- Does not show any perf impact
+        -- UnboxedTuples        -- interferes with (#.)
+
+common optimization-options
+  if flag(opt)
+    ghc-options: -O2
+                 -fdicts-strict
+                 -fspec-constr-recursive=16
+                 -fmax-worker-args=16
+
+  -- For this to be effective it must come after the -O2 option
+  if flag(internal-dev) || !flag(opt)
+    ghc-options: -fno-ignore-asserts
+
+  if flag(fusion-plugin)
+    ghc-options: -fplugin Fusion.Plugin
+
+
+common threading-options
+  ghc-options:  -threaded
+                -with-rtsopts=-N
+
+-- We need optimization options here to optimize internal (non-inlined)
+-- versions of functions. Also, we have some benchmarking inspection tests
+-- part of the library when built with --benchmarks flag. Thos tests fail
+-- if we do not use optimization options here. It was observed that due to
+-- -O2 here some concurrent/nested benchmarks improved and others regressed.
+-- We can investigate a bit more here why the regression occurred.
+common lib-options
+  import: compile-options, optimization-options, default-extensions
+
+common test-options
+  import: lib-options
+        , threading-options
+  ghc-options: -rtsopts -fno-ignore-asserts
+  hs-source-dirs: test
+  build-depends: streamly-core
+               , streamly
+               , streamly-fsevents
+               , base
+               , hspec
+               , directory
+               , filepath
+               , temporary
+  if flag(fusion-plugin)
+    build-depends:
+      fusion-plugin     >= 0.2   && < 0.3
+
+-------------------------------------------------------------------------------
+-- Library
+-------------------------------------------------------------------------------
+
+library
+    import: lib-options
+
+    if impl(ghc >= 8.6)
+      default-extensions: QuantifiedConstraints
+
+    include-dirs: src
+
+    hs-source-dirs: src
+
+    if os(windows)
+          exposed-modules: Streamly.Internal.FS.Event.Windows
+
+    if os(darwin)
+          include-dirs:  src/Streamly/Internal
+          c-sources: src/Streamly/Internal/FS/Event/Darwin.c
+          exposed-modules: Streamly.Internal.FS.Event.Darwin
+
+    if os(linux)
+          exposed-modules: Streamly.Internal.FS.Event.Linux
+
+    if os(linux) || os(darwin) || os(windows)
+          exposed-modules: Streamly.FileSystem.Event
+                           Streamly.Internal.FS.Event
+
+    build-depends:
+                       base              >= 4.12  && < 4.22
+                     , streamly-core     == 0.3.0
+
+    if flag(fusion-plugin)
+      build-depends:
+        fusion-plugin     >= 0.2   && < 0.3
+
+    -- For FS.Event module
+    if os(linux)
+      build-depends: directory >= 1.2.2 && < 1.4
+                   , containers >= 0.6.0 && < 0.8
+
+    if os(windows)
+      build-depends: Win32 >= 2.6 && < 2.15
+                   , streamly == 0.11.0
+
+    if os(darwin)
+      build-depends: mtl       >= 2.2.2 && < 2.4
+      frameworks: Cocoa
+
+
+test-suite FileSystem.Event
+  import: test-options
+  type: exitcode-stdio-1.0
+  ghc-options: -main-is Streamly.Test.FileSystem.Event
+  main-is: Streamly/Test/FileSystem/Event.hs
+  other-modules: Streamly.Test.FileSystem.Event.Common
+  if !((os(linux) && impl(ghc >= 9.4)) || os(darwin) || os(windows))
+    buildable: False
+
+test-suite FileSystem.Event.Darwin
+  import: test-options
+  type: exitcode-stdio-1.0
+  main-is: Streamly/Test/FileSystem/Event/Darwin.hs
+  other-modules: Streamly.Test.FileSystem.Event.Common
+  cpp-options: -DFILESYSTEM_EVENT_DARWIN
+  ghc-options: -main-is Streamly.Test.FileSystem.Event.Darwin
+  if !os(darwin)
+    buildable: False
+
+test-suite FileSystem.Event.Linux
+  import: test-options
+  type: exitcode-stdio-1.0
+  main-is: Streamly/Test/FileSystem/Event/Linux.hs
+  other-modules: Streamly.Test.FileSystem.Event.Common
+  cpp-options: -DFILESYSTEM_EVENT_LINUX
+  ghc-options: -main-is Streamly.Test.FileSystem.Event.Linux
+  if impl(ghc < 9.4) || !os(linux)
+    buildable: False
+
+test-suite FileSystem.Event.Windows
+  import: test-options
+  type: exitcode-stdio-1.0
+  main-is: Streamly/Test/FileSystem/Event/Windows.hs
+  other-modules: Streamly.Test.FileSystem.Event.Common
+  cpp-options: -DFILESYSTEM_EVENT_WINDOWS
+  ghc-options: -main-is Streamly.Test.FileSystem.Event.Windows
+  if !os(windows)
+    buildable: False
diff --git a/test/Streamly/Test/FileSystem/Event.hs b/test/Streamly/Test/FileSystem/Event.hs
new file mode 100644
--- /dev/null
+++ b/test/Streamly/Test/FileSystem/Event.hs
@@ -0,0 +1,28 @@
+-- |
+-- Module      : Streamly.Test.FileSystem.Event
+-- Copyright   : (c) 2021 Composewell Technologies
+-- License     : BSD-3-Clause
+-- Maintainer  : streamly@composewell.com
+-- Stability   : experimental
+-- Portability : GHC
+--
+
+module Streamly.Test.FileSystem.Event (main) where
+
+import qualified Streamly.Internal.FS.Event as Event
+import Streamly.Test.FileSystem.Event.Common
+
+moduleName :: String
+moduleName = "FS.Event"
+
+main :: IO ()
+main = do
+    let run = runTests moduleName "non-recursive" Event.watch
+    run DirType commonTests
+    run
+#if defined(CABAL_OS_DARWIN)
+        SymLinkResolvedPath
+#else
+        SymLinkOrigPath
+#endif
+        commonTests
diff --git a/test/Streamly/Test/FileSystem/Event/Common.hs b/test/Streamly/Test/FileSystem/Event/Common.hs
new file mode 100644
--- /dev/null
+++ b/test/Streamly/Test/FileSystem/Event/Common.hs
@@ -0,0 +1,437 @@
+{-# OPTIONS_GHC -Wno-deprecations #-}
+
+-- |
+-- Module      : Streamly.Test.FileSystem.Event.Common
+-- Copyright   : (c) 2020 Composewell Technologies
+-- License     : BSD-3-Clause
+-- Maintainer  : streamly@composewell.com
+-- Stability   : experimental
+-- Portability : GHC
+--
+module Streamly.Test.FileSystem.Event.Common
+    ( TestDesc
+
+    -- * Running tests
+    , runTests
+    , WatchRootType (..)
+
+    -- * Event predicates
+    , dirEvent
+    , fileEvent
+
+    -- * Tests
+    , dirCreate
+    , dirCreateWithParent
+    , dirDelete
+    , dirMove
+    , rootDirMove
+
+    , fileCreate
+    , fileCreateWithParent
+    , fileDelete
+    , fileModify
+    , fileMove
+    , rootFileMove
+
+    , commonTests
+    , commonRecTests
+    )
+
+where
+
+import Debug.Trace (trace)
+import Control.Concurrent (MVar, newEmptyMVar, putMVar, takeMVar, threadDelay)
+import Control.Monad (when)
+import Data.Bifunctor (first)
+import Data.Function ((&))
+import Data.List.NonEmpty (NonEmpty)
+import System.Directory
+    ( createDirectory
+    , createDirectoryIfMissing
+    , createDirectoryLink
+    , doesDirectoryExist
+    , doesFileExist
+    , removeFile
+    , removePathForcibly
+    , renameDirectory
+    , renamePath
+    )
+import System.FilePath ((</>), takeDirectory)
+import System.IO
+    ( BufferMode(..), hSetBuffering, stdout, IOMode (WriteMode), openFile
+    , hClose)
+import System.IO.Temp (withSystemTempDirectory)
+import Streamly.Internal.FileSystem.Path (Path)
+
+import qualified Data.List.NonEmpty as NonEmpty
+import qualified Streamly.Internal.Data.Stream as Stream
+import qualified Streamly.Internal.Data.Stream.Prelude as Stream
+import qualified Streamly.Internal.FileSystem.Path as Path
+
+#if defined(FILESYSTEM_EVENT_LINUX)
+import Streamly.Internal.FS.Event.Linux (Event)
+import qualified Streamly.Internal.FS.Event.Linux as Event
+#elif defined(FILESYSTEM_EVENT_DARWIN)
+import Streamly.Internal.FS.Event.Darwin (Event)
+import qualified Streamly.Internal.FS.Event.Darwin as Event
+#elif defined(FILESYSTEM_EVENT_WINDOWS)
+import Streamly.Internal.FS.Event.Windows (Event)
+import qualified Streamly.Internal.FS.Event.Windows as Event
+#else
+import Streamly.Internal.FS.Event (Event)
+import qualified Streamly.Internal.FS.Event as Event
+#endif
+
+import Test.Hspec
+
+-------------------------------------------------------------------------------
+-- Check generated events
+-------------------------------------------------------------------------------
+
+type EventChecker =
+       FilePath  -- watch root
+    -> FilePath  -- watch target, target dir if root is a symlink
+    -> MVar ()   -- mvar to sync file system ops and the watch
+    -> [(String, Event -> Bool)] -- expected events
+    -> IO ()
+type EventWatcher = NonEmpty Path -> Stream.Stream IO Event.Event
+
+eventMatches :: Event -> (String, Event -> Bool) -> Bool
+eventMatches ev (expectedPath, f) =
+    trace ("paths: " ++ show evPath ++ " " ++ show expectedPath)
+        (evPath == expectedPath && f ev)
+
+    where
+
+    evPath = Path.toString (Event.getAbsPath ev)
+
+checkEvents :: EventWatcher -> EventChecker
+checkEvents watcher rootPath targetPath mvar matchList = do
+    putStrLn ("Watching on root [" <> rootPath
+             <> "] for [" <> targetPath <> "]")
+
+    let matchList1 = fmap (first (targetPath </>)) matchList
+        finder xs ev = filter (not . eventMatches ev) xs
+
+    paths <- mapM Path.fromString [rootPath]
+    watcher (NonEmpty.fromList paths)
+        & Stream.before (putMVar mvar ())
+        & Stream.trace (putStrLn . Event.showEvent)
+        & Stream.scanl' finder matchList1
+        & Stream.takeWhile (not . null)
+        & Stream.drain
+
+-------------------------------------------------------------------------------
+-- Run tests
+-------------------------------------------------------------------------------
+
+type TestDesc =
+    ( String            -- test description
+    , FilePath -> IO () -- pre test operation, arg is path of the watch root.
+    , FilePath -> IO () -- file system action, arg is path of the watch root.
+    , [(String, Event -> Bool)] -- expected events (Absolute Path, predicate)
+    )
+
+-- | Whether watch root is a symlink and if so then what's the behavior
+data WatchRootType =
+      DirType             -- watch root is a directory
+    | FileType            -- watch root is a file
+    | SymLinkResolvedPath -- symlink to a directory,
+                          -- Event contains path via the resolved dir
+    | SymLinkOrigPath     -- symlink to a directory,
+                          -- Event contains path via the original symlink
+    deriving Show
+
+driver :: EventChecker -> WatchRootType -> TestDesc -> SpecWith ()
+driver checker symlinkStyle (desc, pre, ops, expected) =
+    it desc $ runOneTest `shouldReturn` ()
+
+    where
+
+    fseventDir :: String
+    fseventDir = "fsevent_dir"
+
+    runOneTest = do
+            sync <- newEmptyMVar
+            withSystemTempDirectory fseventDir $ \fp -> do
+                let root = fp </> "watch-root"
+                target <-
+                    case symlinkStyle of
+                        DirType -> do
+                            createDirectory root
+                            return root
+                        FileType -> do
+                            openFile root WriteMode >>= hClose
+                            return root
+                        SymLinkResolvedPath -> do
+                            -- root -> target
+                            let tgt = fp </> "watch-root-real"
+                            createDirectory tgt
+                            createDirectoryLink tgt root
+                            return tgt
+                        SymLinkOrigPath -> do
+                            -- root -> target
+                            let tgt = fp </> "watch-root-real"
+                            createDirectory tgt
+                            createDirectoryLink tgt root
+                            return root
+
+                -- XXX On macOS we seem to get the watch root create events
+                -- even though they occur before the watch is started.  Even if
+                -- we add a delay here.
+                startWatchAndCheck root target sync
+
+    startWatchAndCheck root target sync = do
+            putStrLn ("Before pre op: root [" <> root
+                    <> "] target [" <> target <> "]")
+            pre root
+            putStrLn ("After pre op: root [" <> root
+                    <> "] target [" <> target <> "]")
+            -- XXX On macOS the events from pre ops also seem to be bundled
+            -- with the events occurred after the watch is started.
+            let check = checker root target sync expected
+                fsOps = Stream.fromEffect $ runFSOps root sync
+            Stream.drain
+                $ Stream.parListEagerFst [Stream.fromEffect check, fsOps]
+
+    runFSOps fp sync = do
+        -- We put the MVar before the event watcher starts to run but that does
+        -- not ensure that the event watcher has actually started. So we need a
+        -- delay as well. Do we?
+        takeMVar sync >> threadDelay 200000
+        putStrLn ("Before fs ops: root [" <> fp)
+        ops fp
+        putStrLn ("After fs ops: root [" <> fp)
+        threadDelay 10000000
+        error $ fp <> ": Time out occurred before event watcher could terminate"
+
+-------------------------------------------------------------------------------
+-- Test descriptions
+-------------------------------------------------------------------------------
+
+dirEvent, fileEvent :: (Event -> Bool) -> Event -> Bool
+
+#if defined(FILESYSTEM_EVENT_DARWIN)
+dirEvent f ev = Event.isDir ev && f ev
+fileEvent f ev = Event.isFile ev && f ev
+#elif defined(FILESYSTEM_EVENT_LINUX)
+dirEvent f ev = Event.isDir ev && f ev
+fileEvent f ev = not (Event.isDir ev) && f ev
+#else
+dirEvent = id
+fileEvent = id
+#endif
+
+-- XXX Tests for root as a regular file instead of dir?
+-- XXX Add symlink and hardlink tests
+-- XXX Add exception condition tests
+
+-------------------------------------------------------------------------------
+-- Dir tests
+-------------------------------------------------------------------------------
+
+createParent :: FilePath -> FilePath -> IO ()
+createParent file parent = do
+    createDirectoryIfMissing True (takeDirectory (parent </> file))
+
+createDirWithParent :: FilePath -> FilePath -> IO ()
+createDirWithParent dir parent =
+    when (not (null dir)) $ createDirectoryIfMissing True (parent </> dir)
+
+createDir :: FilePath -> FilePath -> IO ()
+createDir dir parent =
+    when (not (null dir)) $ createDirectory (parent </> dir)
+
+-- | Create the dir along with its parent dir during the test. This is
+-- especially useful to detect a race in Linux case where the watch for a
+-- directory is added in event processing, so if the the child directory is
+-- created before the watch was installed then we may miss some events.
+dirCreateWithParent ::
+    String -> (String -> [([Char], Event -> Bool)]) -> TestDesc
+dirCreateWithParent dir events =
+    ( "dir created (" ++ dir ++ ")"
+    , const (return ())
+    , createDirWithParent dir
+    , events dir
+    )
+
+dirCreate :: String -> (String -> [([Char], Event -> Bool)]) -> TestDesc
+dirCreate dir events =
+    ( "dir created (" ++ dir ++ ")"
+    , createParent dir
+    , createDir dir
+    , events dir
+    )
+
+dirDelete :: String -> (String -> [([Char], Event -> Bool)]) -> TestDesc
+dirDelete dir events =
+      ( "dir deleted (" ++ dir ++ ")"
+      , createDirWithParent dir
+      , \fp -> removePathForcibly (fp </> dir)
+      , events dir
+      )
+
+dirMove ::
+       String
+    -> String
+    -> (String -> String -> [(String, Event -> Bool)])
+    -> TestDesc
+dirMove dir1 dir2 events =
+      ( "dir moved (" ++ dir1 ++ " " ++ dir2 ++ ")"
+      , createDirWithParent dir1
+      , \fp -> renameDirectory (fp </> dir1) (fp </> dir2)
+      , events dir1 dir2
+      )
+
+rootDirMove ::
+       String
+    -> (String -> [(String, Event -> Bool)])
+    -> TestDesc
+rootDirMove suffix events =
+      ( "root dir moved" ++ "(" ++ suffix ++ ")"
+      , const (return ())
+      , \fp -> renameDirectory fp (fp <> suffix)
+      , events ""
+      )
+
+-------------------------------------------------------------------------------
+-- File tests
+-------------------------------------------------------------------------------
+
+createFileWithParent :: FilePath -> FilePath -> IO ()
+createFileWithParent file parent = do
+    let filepath = parent </> file
+    let dir = takeDirectory filepath
+    putStrLn $ "createFileWithParent: file ["
+        ++ file ++ "] dir [" ++ dir ++ "]"
+    putStrLn $ "Ensuring dir: " ++ dir
+    createDirectoryIfMissing True dir
+    r <- doesDirectoryExist dir
+    if r
+    then do
+        putStrLn $ "Ensured dir: " ++ dir
+        when (not (null file)) $ do
+            exists <- doesFileExist filepath
+            if not exists
+            then do
+                putStrLn $ "Creating file: " ++ (parent </> file)
+                openFile (parent </> file) WriteMode >>= hClose
+                putStrLn $ "Created file: " ++ (parent </> file)
+            else error $ "File exists: " ++ filepath
+    else error $ "Could not create dir: " ++ dir
+
+createFile :: FilePath -> FilePath -> IO ()
+createFile file parent =
+    openFile (parent </> file) WriteMode >>= hClose
+
+fileCreate :: String -> (String -> [(String, Event -> Bool)]) -> TestDesc
+fileCreate file1 events =
+    ( "File created (" ++ file1 ++ ")"
+    , createParent file1
+    , createFile file1
+    , (file1, fileEvent Event.isCreated) : events file1
+    )
+
+-- | See comments in dirCreateWithParent
+fileCreateWithParent ::
+    String -> (String -> [(String, Event -> Bool)]) -> TestDesc
+fileCreateWithParent file1 events =
+    ( "File created (" ++ file1 ++ ")"
+    , const (return ())
+    , createFileWithParent  file1
+    , (file1, fileEvent Event.isCreated) : events file1
+    )
+
+fileDelete :: String -> (String -> [(String, Event -> Bool)]) -> TestDesc
+fileDelete file1 events =
+    ( "File deleted (" ++ file1 ++ ")"
+    , createFileWithParent file1
+    , \fp -> removeFile (fp </> file1)
+    , events file1
+    )
+
+fileModify :: String -> (String -> [(String, Event -> Bool)]) -> TestDesc
+fileModify file1 events =
+    ( "File modified (" ++ file1 ++ ")"
+    , createFileWithParent file1
+    , \fp -> writeFile (fp </> file1) "Test Data"
+    , (file1, fileEvent Event.isModified) : events file1
+    )
+
+fileMove ::
+       String
+    -> String
+    -> (String -> String -> [(String, Event -> Bool)])
+    -> TestDesc
+fileMove file1 file2 events =
+    ( "File moved (" ++ file1 ++ " " ++ file2 ++ ")"
+    , createFileWithParent file1
+    , \fp -> renamePath (fp </> file1) (fp </> file2)
+    ,     (file1, fileEvent Event.isMoved)
+        : (file2, fileEvent Event.isMoved)
+        : events file1 file2
+    )
+
+rootFileMove :: String -> (String -> [(String, Event -> Bool)]) -> TestDesc
+rootFileMove suffix events =
+    ( "File moved (" ++ suffix ++ ")"
+    , const (return ())
+    , \fp -> renamePath fp (fp <> suffix)
+    , events ""
+    )
+
+-------------------------------------------------------------------------------
+-- Common test bundles
+-------------------------------------------------------------------------------
+
+withParent :: [Char] -> [Char] -> [Char]
+withParent parent file = if null parent then file else parent </> file
+
+testsWithParent :: String -> [TestDesc]
+testsWithParent p =
+    [ dirCreate
+        (withParent p "dir") (\dir -> [(dir, dirEvent Event.isCreated)])
+    , dirDelete
+        (withParent p "dir") (\dir -> [(dir, dirEvent Event.isDeleted)])
+    , dirMove
+        (withParent p "dir1")
+        (withParent p "dir2")
+        (\dir1 dir2 ->
+            [ (dir1, dirEvent Event.isMoved)
+            , (dir2, dirEvent Event.isMoved)
+            ]
+        )
+    , fileCreate (withParent p "file1") (const [])
+    , fileDelete
+        (withParent p "file1")
+        (\file -> [(file, fileEvent Event.isDeleted)])
+    , fileModify (withParent p "file1") (const [])
+    , fileMove (withParent p "file1") (withParent p "file2") (\_ _ -> [])
+    ]
+
+commonTests :: [TestDesc]
+commonTests = testsWithParent ""
+
+commonRecTests :: [TestDesc]
+commonRecTests = testsWithParent "subdir"
+
+-------------------------------------------------------------------------------
+-- Running tests
+-------------------------------------------------------------------------------
+
+runTests ::
+       String
+    -> String
+    -> EventWatcher
+    -> WatchRootType
+    -> [TestDesc]
+    -> IO ()
+runTests modName watchType watcher rootType tests = do
+    hSetBuffering stdout NoBuffering
+    hspec
+        $ describe modName
+        $ describe watchType
+        $ do
+            let checker = checkEvents watcher
+            describe ("Root type " ++ show rootType)
+                    $ mapM_ (driver checker rootType) tests
diff --git a/test/Streamly/Test/FileSystem/Event/Darwin.hs b/test/Streamly/Test/FileSystem/Event/Darwin.hs
new file mode 100644
--- /dev/null
+++ b/test/Streamly/Test/FileSystem/Event/Darwin.hs
@@ -0,0 +1,86 @@
+-- |
+-- Module      : Streamly.Test.FileSystem.Event.Darwin
+-- Copyright   : (c) 2020 Composewell Technologies
+-- License     : BSD-3-Clause
+-- Maintainer  : streamly@composewell.com
+-- Stability   : experimental
+-- Portability : GHC
+--
+module Streamly.Test.FileSystem.Event.Darwin (main) where
+
+import qualified Streamly.Internal.FS.Event.Darwin as Event
+
+import Streamly.Test.FileSystem.Event.Common
+
+moduleName :: String
+moduleName = "FS.Event.Darwin"
+
+-- TODO:
+-- Creation/deletion/move of hard links
+-- Deletion of last hard link
+-- If a directory is a symlink is it followed in recursive mode?
+
+main :: IO ()
+main = do
+    let symLinkRootTests =
+              dirCreateWithParent "subdir/dir"
+                (\dir -> [(dir, dirEvent Event.isCreated)])
+            : fileCreateWithParent "subdir/file"
+                (\file ->
+                    [ (file, fileEvent Event.isCreated)
+                    , (file, fileEvent Event.isAttrsModified)
+                    ]
+                )
+            : fileCreate "file-create-attrs"
+                (\file ->
+                    [ (file, fileEvent Event.isCreated)
+                    , (file, fileEvent Event.isAttrsModified)
+                    ]
+                )
+            : fileModify
+                    "file-mod-attrs"
+                    (\file -> [(file, fileEvent Event.isAttrsModified)])
+            : dirDelete "dir-sec" (\dir ->
+                [ (dir, dirEvent Event.isDeleted)
+                , (dir, dirEvent Event.isSecurityModified)
+                ]
+                )
+            : commonTests
+            ++ commonRecTests
+    let regularRootTests =
+              dirDelete "" (\dir ->
+                [ (dir, dirEvent Event.isDeleted)
+                , (dir, dirEvent Event.isSecurityModified)
+                , (dir, Event.isRootPathEvent)
+                ]
+                )
+            -- The watch root create event always seems to come even though the
+            -- root is created before the watch is started. That may be because
+            -- of batching?
+            -- XXX Need to create watch root after adding the watch, otherwise
+            -- it fails intermittently.
+            -- : dirCreate "" (\dir -> [(dir, dirEvent Event.isCreated)])
+            : rootDirMove "moved" (\src ->
+                [ (src, Event.isRootPathEvent)
+                , (src, Event.isMoved)
+                ])
+            : symLinkRootTests
+
+    let fileRootTests =
+            [ fileDelete "" (\path ->
+                [ (path, Event.isRootPathEvent)
+                , (path, Event.isDeleted)
+                ])
+            , rootFileMove "moved" (\path ->
+                [(path, Event.isRootPathEvent)
+                , (path, Event.isMoved)
+                ])
+            , fileModify "" (const [])
+            ]
+
+    let w = Event.watchWith (Event.setAllEvents True)
+        run = runTests moduleName "recursive" w
+
+    run DirType regularRootTests
+    run SymLinkResolvedPath symLinkRootTests
+    run FileType fileRootTests
diff --git a/test/Streamly/Test/FileSystem/Event/Linux.hs b/test/Streamly/Test/FileSystem/Event/Linux.hs
new file mode 100644
--- /dev/null
+++ b/test/Streamly/Test/FileSystem/Event/Linux.hs
@@ -0,0 +1,208 @@
+-- |
+-- Module      : Streamly.Test.FileSystem.Event.Linux
+-- Copyright   : (c) 2020 Composewell Technologies
+-- License     : BSD-3-Clause
+-- Maintainer  : streamly@composewell.com
+-- Stability   : experimental
+-- Portability : GHC
+--
+module Streamly.Test.FileSystem.Event.Linux (main) where
+
+import Streamly.Internal.FS.Event.Linux (Event)
+-- #if __GLASGOW_HASKELL__ == 902
+#if 0
+import qualified Data.List as List
+#endif
+import qualified Streamly.Internal.FS.Event.Linux as Event
+
+import Streamly.Test.FileSystem.Event.Common
+
+#define DEVBUILD
+
+moduleName :: String
+moduleName = "FS.Event.Linux"
+
+dirTouchEvents :: String -> [([Char], Event -> Bool)]
+dirTouchEvents dir =
+    [ (dir, dirEvent Event.isOpened)
+    , (dir, dirEvent Event.isAccessed)
+    , (dir, dirEvent Event.isNonWriteClosed)
+    ]
+
+dirDelEvents :: String -> [([Char], Event -> Bool)]
+dirDelEvents dir =
+      (dir, dirEvent Event.isDeleted)
+    : (dir, dirEvent Event.isAttrsModified)
+    : dirTouchEvents dir
+
+rootDirDelEvents :: String -> [([Char], Event -> Bool)]
+rootDirDelEvents root =
+      (root, Event.isRootUnwatched)
+    : (root, Event.isRootDeleted)
+    : (root, dirEvent Event.isAttrsModified)
+    : dirTouchEvents root
+
+dirMoveEvents :: [Char] -> [Char] -> [([Char], Event -> Bool)]
+dirMoveEvents src dst =
+    [ (src, dirEvent Event.isMoved)
+    , (src, dirEvent Event.isMovedFrom)
+    , (dst, dirEvent Event.isMoved)
+    , (dst, dirEvent Event.isMovedTo)
+    ]
+
+#ifdef DEVBUILD
+-- In recursive mode all subdirectories are roots therefore they will generate
+-- isRootMoved.
+rootDirMoveEvents :: [Char] -> [Char] -> [([Char], Event -> Bool)]
+rootDirMoveEvents root _ =
+      (root, Event.isRootMoved)
+    : dirTouchEvents root
+
+recDirMoveEvents :: [Char] -> [Char] -> [([Char], Event -> Bool)]
+recDirMoveEvents src dst = dirMoveEvents src dst ++ rootDirMoveEvents src dst
+#endif
+
+fileTouchEvents :: String -> [([Char], Event -> Bool)]
+fileTouchEvents file =
+    [ (file, fileEvent Event.isOpened)
+    , (file, fileEvent Event.isModified)
+    , (file, fileEvent Event.isWriteClosed)
+    ]
+
+fileMoveEvents :: [Char] -> [Char] -> [([Char], Event -> Bool)]
+fileMoveEvents src dst =
+    [ (src, fileEvent Event.isMoved)
+    , (src, fileEvent Event.isMovedFrom)
+    , (dst, fileEvent Event.isMoved)
+    , (dst, fileEvent Event.isMovedTo)
+    ]
+
+-- TODO: add fileRoot tests from macOS test suite
+
+main :: IO ()
+main = do
+    -- We ignore the events on root/parent dir during regular non-root dir/file
+    -- tests.
+
+    -- Tests common to regular root and symlink root cases
+    let regSymTests =
+              fileCreate "file" fileTouchEvents
+            : fileMove "file1" "file2" fileMoveEvents
+            : dirMove "dir1" "dir2" dirMoveEvents
+            : dirDelete "dir" dirDelEvents
+            : commonTests
+
+    let regTests =
+              dirDelete "" rootDirDelEvents
+            : rootDirMove "moved" (\src -> [(src, Event.isRootMoved)])
+            : regSymTests
+
+    let symTests =
+#if 0
+             -- No events occur when a symlink root is moved. when root is a
+             -- symlinked dir, it does not recv touch, isDeleted or
+             -- rootDeleted, rootUnwatched events. We are not seeing
+             -- isAttrModified event as well, so disabling this altogether.
+              dirDelete "" (\dir -> [(dir, dirEvent Event.isAttrsModified)])
+            :
+#endif
+            regSymTests
+
+    let w = Event.watchWith (Event.setAllEvents True)
+        run = runTests moduleName "non-recursive" w
+
+#if 0
+    let failingTests =
+            [ "File deleted (file1)"
+            , "File modified (file1)"
+            , "File moved (file1 file2)"
+            ]
+#endif
+
+    run DirType
+#if 0
+        $ filter (\(desc, _, _, _) -> desc `List.notElem` failingTests)
+#endif
+        regTests
+
+    run SymLinkOrigPath
+#if 0
+        $ filter (\(desc, _, _, _) -> desc `List.notElem` failingTests)
+#endif
+        symTests
+
+    let fileRootTests =
+            [ fileDelete "" (\path ->
+                [ (path, Event.isAttrsModified)
+                , (path, Event.isRootDeleted)
+                , (path, Event.isRootUnwatched)
+                ])
+            , rootFileMove "moved" (\path -> [(path, Event.isRootMoved)])
+            , fileModify "" (\path -> [(path, Event.isOpened)])
+            ]
+
+    run FileType fileRootTests
+
+    let recw = Event.watchWith
+                (Event.setAllEvents True . Event.setRecursiveMode True)
+        runRec = runTests moduleName "recursive" recw
+
+#ifdef DEVBUILD
+    -- In recursive mode all subdirectories are roots therefore they will
+    -- generate isRootDeleted/isRootUnwatched. Also, for subdirectories
+    -- multiple events are generated, once in the parent watch and once in the
+    -- self watch as a root of the watch. Therefore, additional touchEvents are
+    -- generated in this case.
+    --
+    -- XXX We can possibly filter out the duplicate events either from the
+    -- parent or self.
+    let regSymRecTests =
+            -- XXX Nested file create misses the create event due to a race
+            -- : fileCreateWithParent "subdir/file" fileTouchEvents
+              fileCreate "subdir/file" fileTouchEvents
+            : fileMove "subdir/file1" "subdir/file2" fileMoveEvents
+            : dirMove "dir1" "dir2" recDirMoveEvents
+            : dirMove "subdir/dir1" "subdir/dir2" recDirMoveEvents
+            : dirDelete "dir" (\d -> rootDirDelEvents d ++ dirDelEvents d)
+            : dirDelete "subdir/dir" (\d -> rootDirDelEvents d ++ dirDelEvents d)
+            -- XXX Nested dir create misses the create event due to a race
+            -- : dirCreateWithParent "subdir/dir" dirTouchEvents
+            : dirCreate "subdir/dir"
+                (\dir -> (dir, dirEvent Event.isCreated) : dirTouchEvents dir)
+            : dirCreate "dir"
+                (\dir -> (dir, dirEvent Event.isCreated) : dirTouchEvents dir)
+            : commonRecTests
+        recRegTests = regTests ++ regSymRecTests
+        recSymTests = symTests ++ regSymRecTests
+
+    -- XXX these tests fails intermittently for recursive case
+    -- FS.Event.Linux.recursive, Root type SymLinkOrigPath, File deleted (subdir/file1)
+    -- FS.Event.Linux.recursive, Root type SymLinkOrigPath, File modified (subdir/file1)
+    -- FS.Event.Linux.recursive, Root type SymLinkOrigPath, File moved (subdir/file1 subdir/file2)
+    -- FS.Event.Linux.recursive, Root type DirType, File moved (file1 file2)
+    -- FS.Event.Linux.recursive, Root type DirType, File created (file)
+    --      uncaught exception: IOException of type ResourceBusy
+    --      /tmp/fsevent_dir-a5bd0df64c44ab27/watch-root/file: openFile: resource busy (file is locked)
+
+#if 0
+    let failingRecTests = failingTests ++
+            [ "File created (subdir/file)"
+            , "File deleted (subdir/file1)"
+            , "File modified (subdir/file1)"
+            , "File moved (subdir/file1 subdir/file2)"
+            ]
+#endif
+
+    runRec DirType
+#if 0
+        $ filter (\(desc, _, _, _) -> desc `List.notElem` failingRecTests)
+#endif
+        recRegTests
+
+    runRec SymLinkOrigPath
+#if 0
+        $ filter (\(desc, _, _, _) -> desc `List.notElem` failingRecTests)
+#endif
+        recSymTests
+#endif
+    runRec FileType fileRootTests
diff --git a/test/Streamly/Test/FileSystem/Event/Windows.hs b/test/Streamly/Test/FileSystem/Event/Windows.hs
new file mode 100644
--- /dev/null
+++ b/test/Streamly/Test/FileSystem/Event/Windows.hs
@@ -0,0 +1,51 @@
+-- |
+-- Module      : Streamly.Test.FileSystem.Event.Windows
+-- Copyright   : (c) 2020 Composewell Technologies
+-- License     : BSD-3-Clause
+-- Maintainer  : streamly@composewell.com
+-- Stability   : experimental
+-- Portability : GHC
+--
+module Streamly.Test.FileSystem.Event.Windows (main) where
+
+import qualified Streamly.Internal.FS.Event.Windows as Event
+import Streamly.Test.FileSystem.Event.Common
+
+moduleName :: String
+moduleName = "FS.Event.Windows"
+
+-- TODO Test isModified event for parent directories when a file is created or
+-- deleted.
+
+main :: IO ()
+main = do
+    let regularRootTests =
+            commonTests
+        -- The following watch-root deletion test results in:
+        -- C:\tmp\fsevent_dir-e061f0b0a00e1696\watch-root:
+        -- removePathForcibly:RemoveDirectory
+        -- "\\\\?\\C:\\tmp\\fsevent_dir-e061f0b0a00e1696\\watch-root":
+        -- permission denied (The process cannot access the file because it is
+        -- being used by another process.)
+        --
+        -- ++ dirDelete "" (\dir -> [(dir, Event.isDeleted)])
+
+    let w = Event.watchWith (Event.setAllEvents True)
+        run = runTests moduleName "non-recursive" w
+
+    run DirType regularRootTests
+    run SymLinkOrigPath commonTests
+
+    let recTests =
+            [ dirCreateWithParent "subdir\\dir"
+                (\dir -> [(dir, dirEvent Event.isCreated)])
+            , fileCreateWithParent "subdir\\file"
+                (\file -> [(file, fileEvent Event.isCreated)])
+            ] ++ commonRecTests
+
+    let recw = Event.watchWith
+                (Event.setAllEvents True . Event.setRecursiveMode True)
+        runRec = runTests moduleName "recursive" recw
+
+    runRec DirType (regularRootTests ++ recTests)
+    runRec SymLinkOrigPath (commonTests ++ recTests)