diff --git a/System/Posix/Process/Common.hsc b/System/Posix/Process/Common.hsc
--- a/System/Posix/Process/Common.hsc
+++ b/System/Posix/Process/Common.hsc
@@ -318,12 +318,15 @@
   c_waitpid :: CPid -> Ptr CInt -> CInt -> IO CPid
 
 -- | @'getGroupProcessStatus' blk stopped pgid@ calls @waitpid@,
---   returning @'Just' (pid, tc)@, the 'ProcessID' and
---   'ProcessStatus' for any process in group @pgid@ if one is
---   available, 'Nothing' otherwise.  If @blk@ is 'False', then
---   @WNOHANG@ is set in the options for @waitpid@, otherwise not.
---   If @stopped@ is 'True', then @WUNTRACED@ is set in the
---   options for @waitpid@, otherwise not.
+--   returning @'Just' (pid, tc)@, the 'ProcessID' and 'ProcessStatus'
+--   for any process in group @pgid@ if one is available, or 'Nothing'
+--   if there are child processes but none have exited.  If there are
+--   no child processes, then 'getGroupProcessStatus' raises an
+--   'isDoesNotExistError' exception.
+--
+--   If @blk@ is 'False', then @WNOHANG@ is set in the options for
+--   @waitpid@, otherwise not.  If @stopped@ is 'True', then
+--   @WUNTRACED@ is set in the options for @waitpid@, otherwise not.
 getGroupProcessStatus :: Bool
                       -> Bool
                       -> ProcessGroupID
@@ -336,10 +339,15 @@
       0  -> return Nothing
       _  -> do ps <- readWaitStatus wstatp
 	       return (Just (pid, ps))
+
 -- | @'getAnyProcessStatus' blk stopped@ calls @waitpid@, returning
 --   @'Just' (pid, tc)@, the 'ProcessID' and 'ProcessStatus' for any
---   child process if one is available, 'Nothing' otherwise.  If
---   @blk@ is 'False', then @WNOHANG@ is set in the options for
+--   child process if a child process has exited, or 'Nothing' if
+--   there are child processes but none have exited.  If there are no
+--   child processes, then 'getAnyProcessStatus' raises an
+--   'isDoesNotExistError' exception.
+--
+--   If @blk@ is 'False', then @WNOHANG@ is set in the options for
 --   @waitpid@, otherwise not.  If @stopped@ is 'True', then
 --   @WUNTRACED@ is set in the options for @waitpid@, otherwise not.
 getAnyProcessStatus :: Bool -> Bool -> IO (Maybe (ProcessID, ProcessStatus))
diff --git a/configure b/configure
--- a/configure
+++ b/configure
@@ -1,6 +1,6 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.67 for Haskell unix package 2.0.
+# Generated by GNU Autoconf 2.68 for Haskell unix package 2.0.
 #
 # Report bugs to <libraries@haskell.org>.
 #
@@ -91,6 +91,7 @@
 IFS=" ""	$as_nl"
 
 # 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=$PATH_SEPARATOR
@@ -216,11 +217,18 @@
   # We cannot yet assume a decent shell, so we have to provide a
 	# neutralization value for shells without unset; and this also
 	# works around shells that cannot unset nonexistent variables.
+	# Preserve -v and -x to the replacement shell.
 	BASH_ENV=/dev/null
 	ENV=/dev/null
 	(unset BASH_ENV) >/dev/null 2>&1 && unset BASH_ENV ENV
 	export CONFIG_SHELL
-	exec "$CONFIG_SHELL" "$as_myself" ${1+"$@"}
+	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" ${1+"$@"}
 fi
 
     if test x$as_have_required = xno; then :
@@ -1077,7 +1085,7 @@
     $as_echo "$as_me: WARNING: you should use --build, --host, --target" >&2
     expr "x$ac_option" : ".*[^-._$as_cr_alnum]" >/dev/null &&
       $as_echo "$as_me: WARNING: invalid host type: $ac_option" >&2
-    : ${build_alias=$ac_option} ${host_alias=$ac_option} ${target_alias=$ac_option}
+    : "${build_alias=$ac_option} ${host_alias=$ac_option} ${target_alias=$ac_option}"
     ;;
 
   esac
@@ -1373,7 +1381,7 @@
 if $ac_init_version; then
   cat <<\_ACEOF
 Haskell unix package configure 2.0
-generated by GNU Autoconf 2.67
+generated by GNU Autoconf 2.68
 
 Copyright (C) 2010 Free Software Foundation, Inc.
 This configure script is free software; the Free Software Foundation
@@ -1419,7 +1427,7 @@
 
 	ac_retval=1
 fi
-  eval $as_lineno_stack; test "x$as_lineno_stack" = x && { as_lineno=; unset as_lineno;}
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
   as_fn_set_status $ac_retval
 
 } # ac_fn_c_try_compile
@@ -1456,7 +1464,7 @@
 
     ac_retval=1
 fi
-  eval $as_lineno_stack; test "x$as_lineno_stack" = x && { as_lineno=; unset as_lineno;}
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
   as_fn_set_status $ac_retval
 
 } # ac_fn_c_try_cpp
@@ -1469,10 +1477,10 @@
 ac_fn_c_check_header_mongrel ()
 {
   as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
-  if eval "test \"\${$3+set}\"" = set; then :
+  if eval \${$3+:} false; then :
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5
 $as_echo_n "checking for $2... " >&6; }
-if eval "test \"\${$3+set}\"" = set; then :
+if eval \${$3+:} false; then :
   $as_echo_n "(cached) " >&6
 fi
 eval ac_res=\$$3
@@ -1539,7 +1547,7 @@
 esac
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5
 $as_echo_n "checking for $2... " >&6; }
-if eval "test \"\${$3+set}\"" = set; then :
+if eval \${$3+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   eval "$3=\$ac_header_compiler"
@@ -1548,7 +1556,7 @@
 	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
 $as_echo "$ac_res" >&6; }
 fi
-  eval $as_lineno_stack; test "x$as_lineno_stack" = x && { as_lineno=; unset as_lineno;}
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
 
 } # ac_fn_c_check_header_mongrel
 
@@ -1589,7 +1597,7 @@
        ac_retval=$ac_status
 fi
   rm -rf conftest.dSYM conftest_ipa8_conftest.oo
-  eval $as_lineno_stack; test "x$as_lineno_stack" = x && { as_lineno=; unset as_lineno;}
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
   as_fn_set_status $ac_retval
 
 } # ac_fn_c_try_run
@@ -1603,7 +1611,7 @@
   as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5
 $as_echo_n "checking for $2... " >&6; }
-if eval "test \"\${$3+set}\"" = set; then :
+if eval \${$3+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@@ -1621,7 +1629,7 @@
 eval ac_res=\$$3
 	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
 $as_echo "$ac_res" >&6; }
-  eval $as_lineno_stack; test "x$as_lineno_stack" = x && { as_lineno=; unset as_lineno;}
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
 
 } # ac_fn_c_check_header_compile
 
@@ -1666,7 +1674,7 @@
   # interfere with the next link command; also delete a directory that is
   # left behind by Apple's compiler.  We do this before executing the actions.
   rm -rf conftest.dSYM conftest_ipa8_conftest.oo
-  eval $as_lineno_stack; test "x$as_lineno_stack" = x && { as_lineno=; unset as_lineno;}
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
   as_fn_set_status $ac_retval
 
 } # ac_fn_c_try_link
@@ -1679,7 +1687,7 @@
   as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5
 $as_echo_n "checking for $2... " >&6; }
-if eval "test \"\${$3+set}\"" = set; then :
+if eval \${$3+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@@ -1734,7 +1742,7 @@
 eval ac_res=\$$3
 	       { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_res" >&5
 $as_echo "$ac_res" >&6; }
-  eval $as_lineno_stack; test "x$as_lineno_stack" = x && { as_lineno=; unset as_lineno;}
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
 
 } # ac_fn_c_check_func
 
@@ -1911,7 +1919,7 @@
 rm -f conftest.val
 
   fi
-  eval $as_lineno_stack; test "x$as_lineno_stack" = x && { as_lineno=; unset as_lineno;}
+  eval $as_lineno_stack; ${as_lineno_stack:+:} unset as_lineno
   as_fn_set_status $ac_retval
 
 } # ac_fn_c_compute_int
@@ -1920,7 +1928,7 @@
 running configure, to aid debugging if configure makes a mistake.
 
 It was created by Haskell unix package $as_me 2.0, which was
-generated by GNU Autoconf 2.67.  Invocation command line was
+generated by GNU Autoconf 2.68.  Invocation command line was
 
   $ $0 $@
 
@@ -2178,7 +2186,7 @@
       || { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
 $as_echo "$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 ; }
+See \`config.log' for more details" "$LINENO" 5; }
   fi
 done
 
@@ -2287,7 +2295,7 @@
 set dummy ${ac_tool_prefix}gcc; ac_word=$2
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
 $as_echo_n "checking for $ac_word... " >&6; }
-if test "${ac_cv_prog_CC+set}" = set; then :
+if ${ac_cv_prog_CC+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   if test -n "$CC"; then
@@ -2327,7 +2335,7 @@
 set dummy gcc; ac_word=$2
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
 $as_echo_n "checking for $ac_word... " >&6; }
-if test "${ac_cv_prog_ac_ct_CC+set}" = set; then :
+if ${ac_cv_prog_ac_ct_CC+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   if test -n "$ac_ct_CC"; then
@@ -2380,7 +2388,7 @@
 set dummy ${ac_tool_prefix}cc; ac_word=$2
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
 $as_echo_n "checking for $ac_word... " >&6; }
-if test "${ac_cv_prog_CC+set}" = set; then :
+if ${ac_cv_prog_CC+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   if test -n "$CC"; then
@@ -2420,7 +2428,7 @@
 set dummy cc; ac_word=$2
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
 $as_echo_n "checking for $ac_word... " >&6; }
-if test "${ac_cv_prog_CC+set}" = set; then :
+if ${ac_cv_prog_CC+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   if test -n "$CC"; then
@@ -2479,7 +2487,7 @@
 set dummy $ac_tool_prefix$ac_prog; ac_word=$2
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
 $as_echo_n "checking for $ac_word... " >&6; }
-if test "${ac_cv_prog_CC+set}" = set; then :
+if ${ac_cv_prog_CC+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   if test -n "$CC"; then
@@ -2523,7 +2531,7 @@
 set dummy $ac_prog; ac_word=$2
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $ac_word" >&5
 $as_echo_n "checking for $ac_word... " >&6; }
-if test "${ac_cv_prog_ac_ct_CC+set}" = set; then :
+if ${ac_cv_prog_ac_ct_CC+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   if test -n "$ac_ct_CC"; then
@@ -2578,7 +2586,7 @@
 test -z "$CC" && { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
 $as_echo "$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 ; }
+See \`config.log' for more details" "$LINENO" 5; }
 
 # Provide some information about the compiler.
 $as_echo "$as_me:${as_lineno-$LINENO}: checking for C compiler version" >&5
@@ -2693,7 +2701,7 @@
 { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
 $as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
 as_fn_error 77 "C compiler cannot create executables
-See \`config.log' for more details" "$LINENO" 5 ; }
+See \`config.log' for more details" "$LINENO" 5; }
 else
   { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
@@ -2736,7 +2744,7 @@
   { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
 $as_echo "$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 ; }
+See \`config.log' for more details" "$LINENO" 5; }
 fi
 rm -f conftest conftest$ac_cv_exeext
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_exeext" >&5
@@ -2795,7 +2803,7 @@
 $as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
 as_fn_error $? "cannot run C compiled programs.
 If you meant to cross compile, use \`--host'.
-See \`config.log' for more details" "$LINENO" 5 ; }
+See \`config.log' for more details" "$LINENO" 5; }
     fi
   fi
 fi
@@ -2806,7 +2814,7 @@
 ac_clean_files=$ac_clean_files_save
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for suffix of object files" >&5
 $as_echo_n "checking for suffix of object files... " >&6; }
-if test "${ac_cv_objext+set}" = set; then :
+if ${ac_cv_objext+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@@ -2847,7 +2855,7 @@
 { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
 $as_echo "$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 ; }
+See \`config.log' for more details" "$LINENO" 5; }
 fi
 rm -f conftest.$ac_cv_objext conftest.$ac_ext
 fi
@@ -2857,7 +2865,7 @@
 ac_objext=$OBJEXT
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether we are using the GNU C compiler" >&5
 $as_echo_n "checking whether we are using the GNU C compiler... " >&6; }
-if test "${ac_cv_c_compiler_gnu+set}" = set; then :
+if ${ac_cv_c_compiler_gnu+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@@ -2894,7 +2902,7 @@
 ac_save_CFLAGS=$CFLAGS
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking whether $CC accepts -g" >&5
 $as_echo_n "checking whether $CC accepts -g... " >&6; }
-if test "${ac_cv_prog_cc_g+set}" = set; then :
+if ${ac_cv_prog_cc_g+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_save_c_werror_flag=$ac_c_werror_flag
@@ -2972,7 +2980,7 @@
 fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $CC option to accept ISO C89" >&5
 $as_echo_n "checking for $CC option to accept ISO C89... " >&6; }
-if test "${ac_cv_prog_cc_c89+set}" = set; then :
+if ${ac_cv_prog_cc_c89+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_cv_prog_cc_c89=no
@@ -3085,7 +3093,7 @@
   CPP=
 fi
 if test -z "$CPP"; then
-  if test "${ac_cv_prog_CPP+set}" = set; then :
+  if ${ac_cv_prog_CPP+:} false; then :
   $as_echo_n "(cached) " >&6
 else
       # Double quotes because CPP needs to be expanded
@@ -3201,7 +3209,7 @@
   { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
 $as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
 as_fn_error $? "C preprocessor \"$CPP\" fails sanity check
-See \`config.log' for more details" "$LINENO" 5 ; }
+See \`config.log' for more details" "$LINENO" 5; }
 fi
 
 ac_ext=c
@@ -3213,7 +3221,7 @@
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for grep that handles long lines and -e" >&5
 $as_echo_n "checking for grep that handles long lines and -e... " >&6; }
-if test "${ac_cv_path_GREP+set}" = set; then :
+if ${ac_cv_path_GREP+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   if test -z "$GREP"; then
@@ -3276,7 +3284,7 @@
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for egrep" >&5
 $as_echo_n "checking for egrep... " >&6; }
-if test "${ac_cv_path_EGREP+set}" = set; then :
+if ${ac_cv_path_EGREP+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   if echo a | $GREP -E '(a|b)' >/dev/null 2>&1
@@ -3343,7 +3351,7 @@
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for ANSI C header files" >&5
 $as_echo_n "checking for ANSI C header files... " >&6; }
-if test "${ac_cv_header_stdc+set}" = set; then :
+if ${ac_cv_header_stdc+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@@ -3471,7 +3479,7 @@
 
 
 ac_fn_c_check_header_mongrel "$LINENO" "dlfcn.h" "ac_cv_header_dlfcn_h" "$ac_includes_default"
-if test "x$ac_cv_header_dlfcn_h" = x""yes; then :
+if test "x$ac_cv_header_dlfcn_h" = xyes; then :
   BUILD_PACKAGE_BOOL=True
 else
   BUILD_PACKAGE_BOOL=False
@@ -3482,7 +3490,7 @@
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for an ANSI C-conforming const" >&5
 $as_echo_n "checking for an ANSI C-conforming const... " >&6; }
-if test "${ac_cv_c_const+set}" = set; then :
+if ${ac_cv_c_const+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@@ -3570,7 +3578,7 @@
 
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for special C compiler options needed for large files" >&5
 $as_echo_n "checking for special C compiler options needed for large files... " >&6; }
-if test "${ac_cv_sys_largefile_CC+set}" = set; then :
+if ${ac_cv_sys_largefile_CC+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_cv_sys_largefile_CC=no
@@ -3621,7 +3629,7 @@
 
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for _FILE_OFFSET_BITS value needed for large files" >&5
 $as_echo_n "checking for _FILE_OFFSET_BITS value needed for large files... " >&6; }
-if test "${ac_cv_sys_file_offset_bits+set}" = set; then :
+if ${ac_cv_sys_file_offset_bits+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   while :; do
@@ -3690,7 +3698,7 @@
   if test $ac_cv_sys_file_offset_bits = unknown; then
     { $as_echo "$as_me:${as_lineno-$LINENO}: checking for _LARGE_FILES value needed for large files" >&5
 $as_echo_n "checking for _LARGE_FILES value needed for large files... " >&6; }
-if test "${ac_cv_sys_large_files+set}" = set; then :
+if ${ac_cv_sys_large_files+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   while :; do
@@ -3865,7 +3873,7 @@
 for ac_func in nanosleep
 do :
   ac_fn_c_check_func "$LINENO" "nanosleep" "ac_cv_func_nanosleep"
-if test "x$ac_cv_func_nanosleep" = x""yes; then :
+if test "x$ac_cv_func_nanosleep" = xyes; then :
   cat >>confdefs.h <<_ACEOF
 #define HAVE_NANOSLEEP 1
 _ACEOF
@@ -3876,7 +3884,7 @@
 for ac_func in ptsname
 do :
   ac_fn_c_check_func "$LINENO" "ptsname" "ac_cv_func_ptsname"
-if test "x$ac_cv_func_ptsname" = x""yes; then :
+if test "x$ac_cv_func_ptsname" = xyes; then :
   cat >>confdefs.h <<_ACEOF
 #define HAVE_PTSNAME 1
 _ACEOF
@@ -3887,7 +3895,7 @@
 for ac_func in setitimer
 do :
   ac_fn_c_check_func "$LINENO" "setitimer" "ac_cv_func_setitimer"
-if test "x$ac_cv_func_setitimer" = x""yes; then :
+if test "x$ac_cv_func_setitimer" = xyes; then :
   cat >>confdefs.h <<_ACEOF
 #define HAVE_SETITIMER 1
 _ACEOF
@@ -3898,7 +3906,7 @@
 for ac_func in readdir_r
 do :
   ac_fn_c_check_func "$LINENO" "readdir_r" "ac_cv_func_readdir_r"
-if test "x$ac_cv_func_readdir_r" = x""yes; then :
+if test "x$ac_cv_func_readdir_r" = xyes; then :
   cat >>confdefs.h <<_ACEOF
 #define HAVE_READDIR_R 1
 _ACEOF
@@ -3910,7 +3918,7 @@
 # Avoid adding rt if absent or unneeded
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for shm_open in -lrt" >&5
 $as_echo_n "checking for shm_open in -lrt... " >&6; }
-if test "${ac_cv_lib_rt_shm_open+set}" = set; then :
+if ${ac_cv_lib_rt_shm_open+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
@@ -3944,7 +3952,7 @@
 fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_rt_shm_open" >&5
 $as_echo "$ac_cv_lib_rt_shm_open" >&6; }
-if test "x$ac_cv_lib_rt_shm_open" = x""yes; then :
+if test "x$ac_cv_lib_rt_shm_open" = xyes; then :
   EXTRA_LIBS="$EXTRA_LIBS rt" CFLAGS="$CFLAGS -lrt"
 fi
 
@@ -3968,7 +3976,7 @@
 as_fp_Cache=`$as_echo "fp_cv_const_$fp_const_name" | $as_tr_sh`
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking value of $fp_const_name" >&5
 $as_echo_n "checking value of $fp_const_name... " >&6; }
-if eval "test \"\${$as_fp_Cache+set}\"" = set; then :
+if eval \${$as_fp_Cache+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   if ac_fn_c_compute_int "$LINENO" "$fp_const_name" "fp_check_const_result"        "
@@ -4049,7 +4057,7 @@
 ### we'd like to return it; otherwise, we'll fake it.
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking return type of usleep" >&5
 $as_echo_n "checking return type of usleep... " >&6; }
-if test "${fptools_cv_func_usleep_return_type+set}" = set; then :
+if ${fptools_cv_func_usleep_return_type+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@@ -4080,7 +4088,7 @@
 ###  in common use return void.
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking return type of unsetenv" >&5
 $as_echo_n "checking return type of unsetenv... " >&6; }
-if test "${fptools_cv_func_unsetenv_return_type+set}" = set; then :
+if ${fptools_cv_func_unsetenv_return_type+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@@ -4255,7 +4263,7 @@
 for ac_func in openpty
 do :
   ac_fn_c_check_func "$LINENO" "openpty" "ac_cv_func_openpty"
-if test "x$ac_cv_func_openpty" = x""yes; then :
+if test "x$ac_cv_func_openpty" = xyes; then :
   cat >>confdefs.h <<_ACEOF
 #define HAVE_OPENPTY 1
 _ACEOF
@@ -4263,7 +4271,7 @@
 else
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for openpty in -lutil" >&5
 $as_echo_n "checking for openpty in -lutil... " >&6; }
-if test "${ac_cv_lib_util_openpty+set}" = set; then :
+if ${ac_cv_lib_util_openpty+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
@@ -4297,13 +4305,13 @@
 fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_util_openpty" >&5
 $as_echo "$ac_cv_lib_util_openpty" >&6; }
-if test "x$ac_cv_lib_util_openpty" = x""yes; then :
+if test "x$ac_cv_lib_util_openpty" = xyes; then :
   $as_echo "#define HAVE_OPENPTY 1" >>confdefs.h
  EXTRA_LIBS="$EXTRA_LIBS util"
 else
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for openpty in -lbsd" >&5
 $as_echo_n "checking for openpty in -lbsd... " >&6; }
-if test "${ac_cv_lib_bsd_openpty+set}" = set; then :
+if ${ac_cv_lib_bsd_openpty+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
@@ -4337,7 +4345,7 @@
 fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_bsd_openpty" >&5
 $as_echo "$ac_cv_lib_bsd_openpty" >&6; }
-if test "x$ac_cv_lib_bsd_openpty" = x""yes; then :
+if test "x$ac_cv_lib_bsd_openpty" = xyes; then :
   $as_echo "#define HAVE_OPENPTY 1" >>confdefs.h
  EXTRA_LIBS="$EXTRA_LIBS bsd"
 fi
@@ -4381,7 +4389,7 @@
 # Avoid adding dl if absent or unneeded
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for dlopen in -ldl" >&5
 $as_echo_n "checking for dlopen in -ldl... " >&6; }
-if test "${ac_cv_lib_dl_dlopen+set}" = set; then :
+if ${ac_cv_lib_dl_dlopen+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_check_lib_save_LIBS=$LIBS
@@ -4415,7 +4423,7 @@
 fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_dl_dlopen" >&5
 $as_echo "$ac_cv_lib_dl_dlopen" >&6; }
-if test "x$ac_cv_lib_dl_dlopen" = x""yes; then :
+if test "x$ac_cv_lib_dl_dlopen" = xyes; then :
   EXTRA_LIBS="$EXTRA_LIBS dl"
 fi
 
@@ -4457,7 +4465,7 @@
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking build system type" >&5
 $as_echo_n "checking build system type... " >&6; }
-if test "${ac_cv_build+set}" = set; then :
+if ${ac_cv_build+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_build_alias=$build_alias
@@ -4473,7 +4481,7 @@
 $as_echo "$ac_cv_build" >&6; }
 case $ac_cv_build in
 *-*-*) ;;
-*) as_fn_error $? "invalid value of canonical build" "$LINENO" 5 ;;
+*) as_fn_error $? "invalid value of canonical build" "$LINENO" 5;;
 esac
 build=$ac_cv_build
 ac_save_IFS=$IFS; IFS='-'
@@ -4491,7 +4499,7 @@
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking host system type" >&5
 $as_echo_n "checking host system type... " >&6; }
-if test "${ac_cv_host+set}" = set; then :
+if ${ac_cv_host+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   if test "x$host_alias" = x; then
@@ -4506,7 +4514,7 @@
 $as_echo "$ac_cv_host" >&6; }
 case $ac_cv_host in
 *-*-*) ;;
-*) as_fn_error $? "invalid value of canonical host" "$LINENO" 5 ;;
+*) as_fn_error $? "invalid value of canonical host" "$LINENO" 5;;
 esac
 host=$ac_cv_host
 ac_save_IFS=$IFS; IFS='-'
@@ -4524,7 +4532,7 @@
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking target system type" >&5
 $as_echo_n "checking target system type... " >&6; }
-if test "${ac_cv_target+set}" = set; then :
+if ${ac_cv_target+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   if test "x$target_alias" = x; then
@@ -4539,7 +4547,7 @@
 $as_echo "$ac_cv_target" >&6; }
 case $ac_cv_target in
 *-*-*) ;;
-*) as_fn_error $? "invalid value of canonical target" "$LINENO" 5 ;;
+*) as_fn_error $? "invalid value of canonical target" "$LINENO" 5;;
 esac
 target=$ac_cv_target
 ac_save_IFS=$IFS; IFS='-'
@@ -4564,7 +4572,7 @@
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for library containing sem_close" >&5
 $as_echo_n "checking for library containing sem_close... " >&6; }
-if test "${ac_cv_search_sem_close+set}" = set; then :
+if ${ac_cv_search_sem_close+:} false; then :
   $as_echo_n "(cached) " >&6
 else
   ac_func_search_save_LIBS=$LIBS
@@ -4598,11 +4606,11 @@
 fi
 rm -f core conftest.err conftest.$ac_objext \
     conftest$ac_exeext
-  if test "${ac_cv_search_sem_close+set}" = set; then :
+  if ${ac_cv_search_sem_close+:} false; then :
   break
 fi
 done
-if test "${ac_cv_search_sem_close+set}" = set; then :
+if ${ac_cv_search_sem_close+:} false; then :
 
 else
   ac_cv_search_sem_close=no
@@ -4689,10 +4697,21 @@
      :end' >>confcache
 if diff "$cache_file" confcache >/dev/null 2>&1; then :; else
   if test -w "$cache_file"; then
-    test "x$cache_file" != "x/dev/null" &&
+    if test "x$cache_file" != "x/dev/null"; then
       { $as_echo "$as_me:${as_lineno-$LINENO}: updating cache $cache_file" >&5
 $as_echo "$as_me: updating cache $cache_file" >&6;}
-    cat confcache >$cache_file
+      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
     { $as_echo "$as_me:${as_lineno-$LINENO}: not updating unwritable cache $cache_file" >&5
 $as_echo "$as_me: not updating unwritable cache $cache_file" >&6;}
@@ -4724,7 +4743,7 @@
 
 
 
-: ${CONFIG_STATUS=./config.status}
+: "${CONFIG_STATUS=./config.status}"
 ac_write_fail=0
 ac_clean_files_save=$ac_clean_files
 ac_clean_files="$ac_clean_files $CONFIG_STATUS"
@@ -4825,6 +4844,7 @@
 IFS=" ""	$as_nl"
 
 # 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
@@ -5132,7 +5152,7 @@
 # values after options handling.
 ac_log="
 This file was extended by Haskell unix package $as_me 2.0, which was
-generated by GNU Autoconf 2.67.  Invocation command line was
+generated by GNU Autoconf 2.68.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
   CONFIG_HEADERS  = $CONFIG_HEADERS
@@ -5194,7 +5214,7 @@
 ac_cs_config="`$as_echo "$ac_configure_args" | sed 's/^ //; s/[\\""\`\$]/\\\\&/g'`"
 ac_cs_version="\\
 Haskell unix package config.status 2.0
-configured by $0, generated by GNU Autoconf 2.67,
+configured by $0, generated by GNU Autoconf 2.68,
   with options \\"\$ac_cs_config\\"
 
 Copyright (C) 2010 Free Software Foundation, Inc.
@@ -5317,7 +5337,7 @@
     "include/HsUnixConfig.h") CONFIG_HEADERS="$CONFIG_HEADERS include/HsUnixConfig.h" ;;
     "unix.buildinfo") CONFIG_FILES="$CONFIG_FILES unix.buildinfo" ;;
 
-  *) as_fn_error $? "invalid argument: \`$ac_config_target'" "$LINENO" 5 ;;
+  *) as_fn_error $? "invalid argument: \`$ac_config_target'" "$LINENO" 5;;
   esac
 done
 
@@ -5339,9 +5359,10 @@
 # after its creation but before its name has been assigned to `$tmp'.
 $debug ||
 {
-  tmp=
+  tmp= ac_tmp=
   trap 'exit_status=$?
-  { test -z "$tmp" || test ! -d "$tmp" || rm -fr "$tmp"; } && exit $exit_status
+  : "${ac_tmp:=$tmp}"
+  { test ! -d "$ac_tmp" || rm -fr "$ac_tmp"; } && exit $exit_status
 ' 0
   trap 'as_fn_exit 1' 1 2 13 15
 }
@@ -5349,12 +5370,13 @@
 
 {
   tmp=`(umask 077 && mktemp -d "./confXXXXXX") 2>/dev/null` &&
-  test -n "$tmp" && test -d "$tmp"
+  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_FILES section.
 # No need to generate them if there are no CONFIG_FILES.
@@ -5376,7 +5398,7 @@
   ac_cs_awk_cr=$ac_cr
 fi
 
-echo 'BEGIN {' >"$tmp/subs1.awk" &&
+echo 'BEGIN {' >"$ac_tmp/subs1.awk" &&
 _ACEOF
 
 
@@ -5404,7 +5426,7 @@
 rm -f conf$$subs.sh
 
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
-cat >>"\$tmp/subs1.awk" <<\\_ACAWK &&
+cat >>"\$ac_tmp/subs1.awk" <<\\_ACAWK &&
 _ACEOF
 sed -n '
 h
@@ -5452,7 +5474,7 @@
 rm -f conf$$subs.awk
 cat >>$CONFIG_STATUS <<_ACEOF || ac_write_fail=1
 _ACAWK
-cat >>"\$tmp/subs1.awk" <<_ACAWK &&
+cat >>"\$ac_tmp/subs1.awk" <<_ACAWK &&
   for (key in S) S_is_set[key] = 1
   FS = ""
 
@@ -5484,7 +5506,7 @@
   sed "s/$ac_cr\$//; s/$ac_cr/$ac_cs_awk_cr/g"
 else
   cat
-fi < "$tmp/subs1.awk" > "$tmp/subs.awk" \
+fi < "$ac_tmp/subs1.awk" > "$ac_tmp/subs.awk" \
   || as_fn_error $? "could not setup config files machinery" "$LINENO" 5
 _ACEOF
 
@@ -5518,7 +5540,7 @@
 # No need to generate them if there are no CONFIG_HEADERS.
 # This happens for instance with `./config.status Makefile'.
 if test -n "$CONFIG_HEADERS"; then
-cat >"$tmp/defines.awk" <<\_ACAWK ||
+cat >"$ac_tmp/defines.awk" <<\_ACAWK ||
 BEGIN {
 _ACEOF
 
@@ -5530,8 +5552,8 @@
 # handling of long lines.
 ac_delim='%!_!# '
 for ac_last_try in false false :; do
-  ac_t=`sed -n "/$ac_delim/p" confdefs.h`
-  if test -z "$ac_t"; then
+  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
@@ -5632,7 +5654,7 @@
   esac
   case $ac_mode$ac_tag in
   :[FHL]*:*);;
-  :L* | :C*:*) as_fn_error $? "invalid tag \`$ac_tag'" "$LINENO" 5 ;;
+  :L* | :C*:*) as_fn_error $? "invalid tag \`$ac_tag'" "$LINENO" 5;;
   :[FH]-) ac_tag=-:-;;
   :[FH]*) ac_tag=$ac_tag:$ac_tag.in;;
   esac
@@ -5651,7 +5673,7 @@
     for ac_f
     do
       case $ac_f in
-      -) ac_f="$tmp/stdin";;
+      -) 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 $ac_f cannot contain `:'.
@@ -5660,7 +5682,7 @@
 	   [\\/$]*) false;;
 	   *) test -f "$srcdir/$ac_f" && ac_f="$srcdir/$ac_f";;
 	   esac ||
-	   as_fn_error 1 "cannot find input file: \`$ac_f'" "$LINENO" 5 ;;
+	   as_fn_error 1 "cannot find input file: \`$ac_f'" "$LINENO" 5;;
       esac
       case $ac_f in *\'*) ac_f=`$as_echo "$ac_f" | sed "s/'/'\\\\\\\\''/g"`;; esac
       as_fn_append ac_file_inputs " '$ac_f'"
@@ -5686,8 +5708,8 @@
     esac
 
     case $ac_tag in
-    *:-:* | *:-) cat >"$tmp/stdin" \
-      || as_fn_error $? "could not create $ac_file" "$LINENO" 5  ;;
+    *:-:* | *:-) cat >"$ac_tmp/stdin" \
+      || as_fn_error $? "could not create $ac_file" "$LINENO" 5 ;;
     esac
     ;;
   esac
@@ -5812,21 +5834,22 @@
 s&@abs_top_builddir@&$ac_abs_top_builddir&;t t
 $ac_datarootdir_hack
 "
-eval sed \"\$ac_sed_extra\" "$ac_file_inputs" | $AWK -f "$tmp/subs.awk" >$tmp/out \
-  || as_fn_error $? "could not create $ac_file" "$LINENO" 5
+eval sed \"\$ac_sed_extra\" "$ac_file_inputs" | $AWK -f "$ac_tmp/subs.awk" \
+  >$ac_tmp/out || as_fn_error $? "could not create $ac_file" "$LINENO" 5
 
 test -z "$ac_datarootdir_hack$ac_datarootdir_seen" &&
-  { ac_out=`sed -n '/\${datarootdir}/p' "$tmp/out"`; test -n "$ac_out"; } &&
-  { ac_out=`sed -n '/^[	 ]*datarootdir[	 ]*:*=/p' "$tmp/out"`; test -z "$ac_out"; } &&
+  { ac_out=`sed -n '/\${datarootdir}/p' "$ac_tmp/out"`; test -n "$ac_out"; } &&
+  { ac_out=`sed -n '/^[	 ]*datarootdir[	 ]*:*=/p' \
+      "$ac_tmp/out"`; test -z "$ac_out"; } &&
   { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: $ac_file contains a reference to the variable \`datarootdir'
 which seems to be undefined.  Please make sure it is defined" >&5
 $as_echo "$as_me: WARNING: $ac_file contains a reference to the variable \`datarootdir'
 which seems to be undefined.  Please make sure it is defined" >&2;}
 
-  rm -f "$tmp/stdin"
+  rm -f "$ac_tmp/stdin"
   case $ac_file in
-  -) cat "$tmp/out" && rm -f "$tmp/out";;
-  *) rm -f "$ac_file" && mv "$tmp/out" "$ac_file";;
+  -) cat "$ac_tmp/out" && rm -f "$ac_tmp/out";;
+  *) rm -f "$ac_file" && mv "$ac_tmp/out" "$ac_file";;
   esac \
   || as_fn_error $? "could not create $ac_file" "$LINENO" 5
  ;;
@@ -5837,20 +5860,20 @@
   if test x"$ac_file" != x-; then
     {
       $as_echo "/* $configure_input  */" \
-      && eval '$AWK -f "$tmp/defines.awk"' "$ac_file_inputs"
-    } >"$tmp/config.h" \
+      && eval '$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 "$ac_file" "$tmp/config.h" >/dev/null 2>&1; then
+    if diff "$ac_file" "$ac_tmp/config.h" >/dev/null 2>&1; then
       { $as_echo "$as_me:${as_lineno-$LINENO}: $ac_file is unchanged" >&5
 $as_echo "$as_me: $ac_file is unchanged" >&6;}
     else
       rm -f "$ac_file"
-      mv "$tmp/config.h" "$ac_file" \
+      mv "$ac_tmp/config.h" "$ac_file" \
 	|| as_fn_error $? "could not create $ac_file" "$LINENO" 5
     fi
   else
     $as_echo "/* $configure_input  */" \
-      && eval '$AWK -f "$tmp/defines.awk"' "$ac_file_inputs" \
+      && eval '$AWK -f "$ac_tmp/defines.awk"' "$ac_file_inputs" \
       || as_fn_error $? "could not create -" "$LINENO" 5
   fi
  ;;
diff --git a/include/HsUnixConfig.h b/include/HsUnixConfig.h
--- a/include/HsUnixConfig.h
+++ b/include/HsUnixConfig.h
@@ -95,7 +95,7 @@
 #define CONST_SIG_UNBLOCK 1
 
 /* Define to 1 if you have the <bsd/libutil.h> header file. */
-/* #undef HAVE_BSD_LIBUTIL_H */
+#define HAVE_BSD_LIBUTIL_H 1
 
 /* Define if we have /dev/ptc. */
 /* #undef HAVE_DEV_PTC */
@@ -197,10 +197,10 @@
 #define HAVE_SETITIMER 1
 
 /* Define to 1 if you have the `shm_open' function. */
-#define HAVE_SHM_OPEN 1
+/* #undef HAVE_SHM_OPEN */
 
 /* Define to 1 if you have the `shm_unlink' function. */
-#define HAVE_SHM_UNLINK 1
+/* #undef HAVE_SHM_UNLINK */
 
 /* Define to 1 if you have the <signal.h> header file. */
 #define HAVE_SIGNAL_H 1
@@ -287,7 +287,7 @@
 /* #undef USLEEP_RETURNS_VOID */
 
 /* Number of bits in a file offset, on hosts where this is settable. */
-/* #undef _FILE_OFFSET_BITS */
+#define _FILE_OFFSET_BITS 64
 
 /* Define for large files, on AIX-style hosts. */
 /* #undef _LARGE_FILES */
diff --git a/unix.cabal b/unix.cabal
--- a/unix.cabal
+++ b/unix.cabal
@@ -1,5 +1,5 @@
 name:		unix
-version:        2.5.1.0
+version:        2.5.1.1
 license:	BSD3
 license-file:	LICENSE
 maintainer:	libraries@haskell.org