diff --git a/System/Posix/Signals.hsc b/System/Posix/Signals.hsc
--- a/System/Posix/Signals.hsc
+++ b/System/Posix/Signals.hsc
@@ -71,7 +71,7 @@
 
   -- * Signal sets
   SignalSet,
-  emptySignalSet, fullSignalSet, 
+  emptySignalSet, fullSignalSet, reservedSignals,
   addSignal, deleteSignal, inSignalSet,
 
   -- * The process signal mask
@@ -495,6 +495,13 @@
   throwErrnoIfMinus1_ "fullSignalSet" (withForeignPtr fp $ c_sigfillset)
   return (SignalSet fp)
 
+-- | A set of signals reserved for use by the implementation.  In GHC, this will normally
+-- include either `sigVTALRM` or `sigALRM`.
+reservedSignals :: SignalSet
+reservedSignals = addSignal rtsTimerSignal emptySignalSet
+
+foreign import ccall rtsTimerSignal :: CInt
+
 infixr `addSignal`, `deleteSignal`
 addSignal :: Signal -> SignalSet -> SignalSet
 addSignal sig (SignalSet fp1) = unsafePerformIO $ do
@@ -565,9 +572,15 @@
 -- | @awaitSignal iset@ suspends execution until an interrupt is received.
 -- If @iset@ is @Just s@, @awaitSignal@ calls @sigsuspend@, installing
 -- @s@ as the new signal mask before suspending execution; otherwise, it
--- calls @pause@.  @awaitSignal@ returns on receipt of a signal.  If you
--- have installed any signal handlers with @installHandler@, it may be
--- wise to call @yield@ directly after @awaitSignal@ to ensure that the
+-- calls @sigsuspend@ with current signal mask. Note that RTS
+-- scheduler signal (either 'virtualTimerExpired' or 'realTimeAlarm') 
+-- could cause premature termination of this call. It might be necessary to block that
+-- signal before invocation of @awaitSignal@ with 'blockSignals' 'reservedSignals'.
+--
+-- @awaitSignal@ returns when signal was received and processed by a
+-- signal handler, or if the signal could not be caught. If you have
+-- installed any signal handlers with @installHandler@, it may be wise
+-- to call @yield@ directly after @awaitSignal@ to ensure that the
 -- signal handler runs as promptly as possible.
 awaitSignal :: Maybe SignalSet -> IO ()
 awaitSignal maybe_sigset = do
diff --git a/configure b/configure
--- a/configure
+++ b/configure
@@ -1,13 +1,13 @@
 #! /bin/sh
 # Guess values for system-dependent variables and create Makefiles.
-# Generated by GNU Autoconf 2.65 for Haskell unix package 2.0.
+# Generated by GNU Autoconf 2.67 for Haskell unix package 2.0.
 #
 # Report bugs to <libraries@haskell.org>.
 #
 #
 # Copyright (C) 1992, 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001,
-# 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation,
-# Inc.
+# 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software
+# Foundation, Inc.
 #
 #
 # This configure script is free software; the Free Software Foundation
@@ -319,7 +319,7 @@
       test -d "$as_dir" && break
     done
     test -z "$as_dirs" || eval "mkdir $as_dirs"
-  } || test -d "$as_dir" || as_fn_error "cannot create directory $as_dir"
+  } || test -d "$as_dir" || as_fn_error $? "cannot create directory $as_dir"
 
 
 } # as_fn_mkdir_p
@@ -359,19 +359,19 @@
 fi # as_fn_arith
 
 
-# as_fn_error ERROR [LINENO LOG_FD]
-# ---------------------------------
+# 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 $?, using 1 if that was 0.
+# script with STATUS, using 1 if that was 0.
 as_fn_error ()
 {
-  as_status=$?; test $as_status -eq 0 && as_status=1
-  if test "$3"; then
-    as_lineno=${as_lineno-"$2"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
-    $as_echo "$as_me:${as_lineno-$LINENO}: error: $1" >&$3
+  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
+    $as_echo "$as_me:${as_lineno-$LINENO}: error: $2" >&$4
   fi
-  $as_echo "$as_me: error: $1" >&2
+  $as_echo "$as_me: error: $2" >&2
   as_fn_exit $as_status
 } # as_fn_error
 
@@ -533,7 +533,7 @@
 exec 6>&1
 
 # Name of the host.
-# hostname on some systems (SVR3.2, Linux) returns a bogus exit status,
+# 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`
 
@@ -596,9 +596,6 @@
 
 ac_subst_vars='LTLIBOBJS
 LIBOBJS
-PTHREAD_LIBS
-PTHREAD_LDFLAGS
-PTHREAD_CFLAGS
 target_os
 target_vendor
 target_cpu
@@ -738,8 +735,9 @@
   fi
 
   case $ac_option in
-  *=*)	ac_optarg=`expr "X$ac_option" : '[^=]*=\(.*\)'` ;;
-  *)	ac_optarg=yes ;;
+  *=?*) ac_optarg=`expr "X$ac_option" : '[^=]*=\(.*\)'` ;;
+  *=)   ac_optarg= ;;
+  *)    ac_optarg=yes ;;
   esac
 
   # Accept the important Cygnus configure options, so we can diagnose typos.
@@ -784,7 +782,7 @@
     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"
+      as_fn_error $? "invalid feature name: $ac_useropt"
     ac_useropt_orig=$ac_useropt
     ac_useropt=`$as_echo "$ac_useropt" | sed 's/[-+.]/_/g'`
     case $ac_user_opts in
@@ -810,7 +808,7 @@
     ac_useropt=`expr "x$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"
+      as_fn_error $? "invalid feature name: $ac_useropt"
     ac_useropt_orig=$ac_useropt
     ac_useropt=`$as_echo "$ac_useropt" | sed 's/[-+.]/_/g'`
     case $ac_user_opts in
@@ -1014,7 +1012,7 @@
     ac_useropt=`expr "x$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"
+      as_fn_error $? "invalid package name: $ac_useropt"
     ac_useropt_orig=$ac_useropt
     ac_useropt=`$as_echo "$ac_useropt" | sed 's/[-+.]/_/g'`
     case $ac_user_opts in
@@ -1030,7 +1028,7 @@
     ac_useropt=`expr "x$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"
+      as_fn_error $? "invalid package name: $ac_useropt"
     ac_useropt_orig=$ac_useropt
     ac_useropt=`$as_echo "$ac_useropt" | sed 's/[-+.]/_/g'`
     case $ac_user_opts in
@@ -1060,8 +1058,8 @@
   | --x-librar=* | --x-libra=* | --x-libr=* | --x-lib=* | --x-li=* | --x-l=*)
     x_libraries=$ac_optarg ;;
 
-  -*) as_fn_error "unrecognized option: \`$ac_option'
-Try \`$0 --help' for more information."
+  -*) as_fn_error $? "unrecognized option: \`$ac_option'
+Try \`$0 --help' for more information"
     ;;
 
   *=*)
@@ -1069,7 +1067,7 @@
     # 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'" ;;
+      as_fn_error $? "invalid variable name: \`$ac_envvar'" ;;
     esac
     eval $ac_envvar=\$ac_optarg
     export $ac_envvar ;;
@@ -1087,13 +1085,13 @@
 
 if test -n "$ac_prev"; then
   ac_option=--`echo $ac_prev | sed 's/_/-/g'`
-  as_fn_error "missing argument to $ac_option"
+  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" ;;
+    fatal) as_fn_error $? "unrecognized options: $ac_unrecognized_opts" ;;
     *)     $as_echo "$as_me: WARNING: unrecognized options: $ac_unrecognized_opts" >&2 ;;
   esac
 fi
@@ -1116,7 +1114,7 @@
     [\\/$]* | ?:[\\/]* )  continue;;
     NONE | '' ) case $ac_var in *prefix ) continue;; esac;;
   esac
-  as_fn_error "expected an absolute directory name for --$ac_var: $ac_val"
+  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: `$host'
@@ -1130,8 +1128,8 @@
 if test "x$host_alias" != x; then
   if test "x$build_alias" = x; then
     cross_compiling=maybe
-    $as_echo "$as_me: WARNING: If you wanted to set the --build type, don't use --host.
-    If a cross compiler is detected then cross compile mode will be used." >&2
+    $as_echo "$as_me: WARNING: if you wanted to set the --build type, don't use --host.
+    If a cross compiler is detected then cross compile mode will be used" >&2
   elif test "x$build_alias" != "x$host_alias"; then
     cross_compiling=yes
   fi
@@ -1146,9 +1144,9 @@
 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"
+  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"
+  as_fn_error $? "pwd does not report name of working directory"
 
 
 # Find the source files, if location was not specified.
@@ -1187,11 +1185,11 @@
 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"
+  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"
+	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
@@ -1231,7 +1229,7 @@
       --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
+  -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
@@ -1375,9 +1373,9 @@
 if $ac_init_version; then
   cat <<\_ACEOF
 Haskell unix package configure 2.0
-generated by GNU Autoconf 2.65
+generated by GNU Autoconf 2.67
 
-Copyright (C) 2009 Free Software Foundation, Inc.
+Copyright (C) 2010 Free Software Foundation, Inc.
 This configure script is free software; the Free Software Foundation
 gives unlimited permission to copy, distribute and modify it.
 _ACEOF
@@ -1447,7 +1445,7 @@
     mv -f conftest.er1 conftest.err
   fi
   $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
-  test $ac_status = 0; } >/dev/null && {
+  test $ac_status = 0; } > conftest.i && {
 	 test -z "$ac_c_preproc_warn_flag$ac_c_werror_flag" ||
 	 test ! -s conftest.err
        }; then :
@@ -1471,10 +1469,10 @@
 ac_fn_c_check_header_mongrel ()
 {
   as_lineno=${as_lineno-"$1"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
-  if { as_var=$3; eval "test \"\${$as_var+set}\" = set"; }; then :
+  if eval "test \"\${$3+set}\"" = set; then :
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5
 $as_echo_n "checking for $2... " >&6; }
-if { as_var=$3; eval "test \"\${$as_var+set}\" = set"; }; then :
+if eval "test \"\${$3+set}\"" = set; then :
   $as_echo_n "(cached) " >&6
 fi
 eval ac_res=\$$3
@@ -1510,7 +1508,7 @@
 else
   ac_header_preproc=no
 fi
-rm -f conftest.err conftest.$ac_ext
+rm -f conftest.err conftest.i conftest.$ac_ext
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_header_preproc" >&5
 $as_echo "$ac_header_preproc" >&6; }
 
@@ -1533,17 +1531,15 @@
 $as_echo "$as_me: WARNING: $2:     section \"Present But Cannot Be Compiled\"" >&2;}
     { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: $2: proceeding with the compiler's result" >&5
 $as_echo "$as_me: WARNING: $2: proceeding with the compiler's result" >&2;}
-( cat <<\_ASBOX
-## ------------------------------------ ##
+( $as_echo "## ------------------------------------ ##
 ## Report this to libraries@haskell.org ##
-## ------------------------------------ ##
-_ASBOX
+## ------------------------------------ ##"
      ) | sed "s/^/$as_me: WARNING:     /" >&2
     ;;
 esac
   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for $2" >&5
 $as_echo_n "checking for $2... " >&6; }
-if { as_var=$3; eval "test \"\${$as_var+set}\" = set"; }; then :
+if eval "test \"\${$3+set}\"" = set; then :
   $as_echo_n "(cached) " >&6
 else
   eval "$3=\$ac_header_compiler"
@@ -1607,7 +1603,7 @@
   as_lineno=${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 { as_var=$3; eval "test \"\${$as_var+set}\" = set"; }; then :
+if eval "test \"\${$3+set}\"" = set; then :
   $as_echo_n "(cached) " >&6
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@@ -1683,7 +1679,7 @@
   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 { as_var=$3; eval "test \"\${$as_var+set}\" = set"; }; then :
+if eval "test \"\${$3+set}\"" = set; then :
   $as_echo_n "(cached) " >&6
 else
   cat confdefs.h - <<_ACEOF >conftest.$ac_ext
@@ -1924,7 +1920,7 @@
 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 2.65.  Invocation command line was
+generated by GNU Autoconf 2.67.  Invocation command line was
 
   $ $0 $@
 
@@ -2034,11 +2030,9 @@
   {
     echo
 
-    cat <<\_ASBOX
-## ---------------- ##
+    $as_echo "## ---------------- ##
 ## Cache variables. ##
-## ---------------- ##
-_ASBOX
+## ---------------- ##"
     echo
     # The following way of writing the cache mishandles newlines in values,
 (
@@ -2072,11 +2066,9 @@
 )
     echo
 
-    cat <<\_ASBOX
-## ----------------- ##
+    $as_echo "## ----------------- ##
 ## Output variables. ##
-## ----------------- ##
-_ASBOX
+## ----------------- ##"
     echo
     for ac_var in $ac_subst_vars
     do
@@ -2089,11 +2081,9 @@
     echo
 
     if test -n "$ac_subst_files"; then
-      cat <<\_ASBOX
-## ------------------- ##
+      $as_echo "## ------------------- ##
 ## File substitutions. ##
-## ------------------- ##
-_ASBOX
+## ------------------- ##"
       echo
       for ac_var in $ac_subst_files
       do
@@ -2107,11 +2097,9 @@
     fi
 
     if test -s confdefs.h; then
-      cat <<\_ASBOX
-## ----------- ##
+      $as_echo "## ----------- ##
 ## confdefs.h. ##
-## ----------- ##
-_ASBOX
+## ----------- ##"
       echo
       cat confdefs.h
       echo
@@ -2166,7 +2154,12 @@
 ac_site_file1=NONE
 ac_site_file2=NONE
 if test -n "$CONFIG_SITE"; then
-  ac_site_file1=$CONFIG_SITE
+  # We do not want a PATH search for config.site.
+  case $CONFIG_SITE in #((
+    -*)  ac_site_file1=./$CONFIG_SITE;;
+    */*) ac_site_file1=$CONFIG_SITE;;
+    *)   ac_site_file1=./$CONFIG_SITE;;
+  esac
 elif test "x$prefix" != xNONE; then
   ac_site_file1=$prefix/share/config.site
   ac_site_file2=$prefix/etc/config.site
@@ -2181,7 +2174,11 @@
     { $as_echo "$as_me:${as_lineno-$LINENO}: loading site script $ac_site_file" >&5
 $as_echo "$as_me: loading site script $ac_site_file" >&6;}
     sed 's/^/| /' "$ac_site_file" >&5
-    . "$ac_site_file"
+    . "$ac_site_file" \
+      || { { $as_echo "$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 ; }
   fi
 done
 
@@ -2257,7 +2254,7 @@
 $as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
   { $as_echo "$as_me:${as_lineno-$LINENO}: error: changes in the environment can compromise the build" >&5
 $as_echo "$as_me: error: changes in the environment can compromise the build" >&2;}
-  as_fn_error "run \`make distclean' and/or \`rm $cache_file' and start over" "$LINENO" 5
+  as_fn_error $? "run \`make distclean' and/or \`rm $cache_file' and start over" "$LINENO" 5
 fi
 ## -------------------- ##
 ## Main body of script. ##
@@ -2580,8 +2577,8 @@
 
 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; }
+as_fn_error $? "no acceptable C compiler found in \$PATH
+See \`config.log' for more details" "$LINENO" 5 ; }
 
 # Provide some information about the compiler.
 $as_echo "$as_me:${as_lineno-$LINENO}: checking for C compiler version" >&5
@@ -2695,9 +2692,8 @@
 
 { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
 $as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
-{ as_fn_set_status 77
-as_fn_error "C compiler cannot create executables
-See \`config.log' for more details." "$LINENO" 5; }; }
+as_fn_error 77 "C compiler cannot create executables
+See \`config.log' for more details" "$LINENO" 5 ; }
 else
   { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
@@ -2739,8 +2735,8 @@
 else
   { { $as_echo "$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; }
+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
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_exeext" >&5
@@ -2797,9 +2793,9 @@
     else
 	{ { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
 $as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
-as_fn_error "cannot run C compiled programs.
+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
@@ -2850,8 +2846,8 @@
 
 { { $as_echo "$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; }
+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
@@ -3119,7 +3115,7 @@
   # Broken: fails on valid input.
 continue
 fi
-rm -f conftest.err conftest.$ac_ext
+rm -f conftest.err conftest.i conftest.$ac_ext
 
   # OK, works on sane cases.  Now check whether nonexistent headers
   # can be detected and how.
@@ -3135,11 +3131,11 @@
 ac_preproc_ok=:
 break
 fi
-rm -f conftest.err conftest.$ac_ext
+rm -f conftest.err conftest.i conftest.$ac_ext
 
 done
 # Because of `break', _AC_PREPROC_IFELSE's cleaning code was skipped.
-rm -f conftest.err conftest.$ac_ext
+rm -f conftest.i conftest.err conftest.$ac_ext
 if $ac_preproc_ok; then :
   break
 fi
@@ -3178,7 +3174,7 @@
   # Broken: fails on valid input.
 continue
 fi
-rm -f conftest.err conftest.$ac_ext
+rm -f conftest.err conftest.i conftest.$ac_ext
 
   # OK, works on sane cases.  Now check whether nonexistent headers
   # can be detected and how.
@@ -3194,18 +3190,18 @@
 ac_preproc_ok=:
 break
 fi
-rm -f conftest.err conftest.$ac_ext
+rm -f conftest.err conftest.i conftest.$ac_ext
 
 done
 # Because of `break', _AC_PREPROC_IFELSE's cleaning code was skipped.
-rm -f conftest.err conftest.$ac_ext
+rm -f conftest.i conftest.err conftest.$ac_ext
 if $ac_preproc_ok; then :
 
 else
   { { $as_echo "$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; }
+as_fn_error $? "C preprocessor \"$CPP\" fails sanity check
+See \`config.log' for more details" "$LINENO" 5 ; }
 fi
 
 ac_ext=c
@@ -3266,7 +3262,7 @@
   done
 IFS=$as_save_IFS
   if test -z "$ac_cv_path_GREP"; then
-    as_fn_error "no acceptable grep could be found in $PATH$PATH_SEPARATOR/usr/xpg4/bin" "$LINENO" 5
+    as_fn_error $? "no acceptable grep could be found in $PATH$PATH_SEPARATOR/usr/xpg4/bin" "$LINENO" 5
   fi
 else
   ac_cv_path_GREP=$GREP
@@ -3332,7 +3328,7 @@
   done
 IFS=$as_save_IFS
   if test -z "$ac_cv_path_EGREP"; then
-    as_fn_error "no acceptable egrep could be found in $PATH$PATH_SEPARATOR/usr/xpg4/bin" "$LINENO" 5
+    as_fn_error $? "no acceptable egrep could be found in $PATH$PATH_SEPARATOR/usr/xpg4/bin" "$LINENO" 5
   fi
 else
   ac_cv_path_EGREP=$EGREP
@@ -3464,8 +3460,7 @@
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_compile "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default
 "
-eval as_val=\$$as_ac_Header
-   if test "x$as_val" = x""yes; then :
+if eval test \"x\$"$as_ac_Header"\" = x"yes"; then :
   cat >>confdefs.h <<_ACEOF
 #define `$as_echo "HAVE_$ac_header" | $as_tr_cpp` 1
 _ACEOF
@@ -3769,8 +3764,7 @@
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
-eval as_val=\$$as_ac_Header
-   if test "x$as_val" = x""yes; then :
+if eval test \"x\$"$as_ac_Header"\" = x"yes"; then :
   cat >>confdefs.h <<_ACEOF
 #define `$as_echo "HAVE_$ac_header" | $as_tr_cpp` 1
 _ACEOF
@@ -3783,8 +3777,7 @@
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
-eval as_val=\$$as_ac_Header
-   if test "x$as_val" = x""yes; then :
+if eval test \"x\$"$as_ac_Header"\" = x"yes"; then :
   cat >>confdefs.h <<_ACEOF
 #define `$as_echo "HAVE_$ac_header" | $as_tr_cpp` 1
 _ACEOF
@@ -3797,8 +3790,7 @@
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
-eval as_val=\$$as_ac_Header
-   if test "x$as_val" = x""yes; then :
+if eval test \"x\$"$as_ac_Header"\" = x"yes"; then :
   cat >>confdefs.h <<_ACEOF
 #define `$as_echo "HAVE_$ac_header" | $as_tr_cpp` 1
 _ACEOF
@@ -3811,8 +3803,7 @@
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
-eval as_val=\$$as_ac_Header
-   if test "x$as_val" = x""yes; then :
+if eval test \"x\$"$as_ac_Header"\" = x"yes"; then :
   cat >>confdefs.h <<_ACEOF
 #define `$as_echo "HAVE_$ac_header" | $as_tr_cpp` 1
 _ACEOF
@@ -3825,8 +3816,7 @@
 do :
   as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
 ac_fn_c_check_header_mongrel "$LINENO" "$ac_header" "$as_ac_Header" "$ac_includes_default"
-eval as_val=\$$as_ac_Header
-   if test "x$as_val" = x""yes; then :
+if eval test \"x\$"$as_ac_Header"\" = x"yes"; then :
   cat >>confdefs.h <<_ACEOF
 #define `$as_echo "HAVE_$ac_header" | $as_tr_cpp` 1
 _ACEOF
@@ -3840,8 +3830,7 @@
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
-eval as_val=\$$as_ac_var
-   if test "x$as_val" = x""yes; then :
+if eval test \"x\$"$as_ac_var"\" = x"yes"; then :
   cat >>confdefs.h <<_ACEOF
 #define `$as_echo "HAVE_$ac_func" | $as_tr_cpp` 1
 _ACEOF
@@ -3853,8 +3842,7 @@
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
-eval as_val=\$$as_ac_var
-   if test "x$as_val" = x""yes; then :
+if eval test \"x\$"$as_ac_var"\" = x"yes"; then :
   cat >>confdefs.h <<_ACEOF
 #define `$as_echo "HAVE_$ac_func" | $as_tr_cpp` 1
 _ACEOF
@@ -3866,8 +3854,7 @@
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
-eval as_val=\$$as_ac_var
-   if test "x$as_val" = x""yes; then :
+if eval test \"x\$"$as_ac_var"\" = x"yes"; then :
   cat >>confdefs.h <<_ACEOF
 #define `$as_echo "HAVE_$ac_func" | $as_tr_cpp` 1
 _ACEOF
@@ -3967,8 +3954,7 @@
 do :
   as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var"
-eval as_val=\$$as_ac_var
-   if test "x$as_val" = x""yes; then :
+if eval test \"x\$"$as_ac_var"\" = x"yes"; then :
   cat >>confdefs.h <<_ACEOF
 #define `$as_echo "HAVE_$ac_func" | $as_tr_cpp` 1
 _ACEOF
@@ -3982,7 +3968,7 @@
 as_fp_Cache=`$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 $fp_const_name... " >&6; }
-if { as_var=$as_fp_Cache; eval "test \"\${$as_var+set}\" = set"; }; then :
+if eval "test \"\${$as_fp_Cache+set}\"" = set; then :
   $as_echo_n "(cached) " >&6
 else
   if ac_fn_c_compute_int "$LINENO" "$fp_const_name" "fp_check_const_result"        "
@@ -4438,16 +4424,22 @@
 # -{l,}pthread goo
 ac_aux_dir=
 for ac_dir in "$srcdir" "$srcdir/.." "$srcdir/../.."; do
-  for ac_t in install-sh install.sh shtool; do
-    if test -f "$ac_dir/$ac_t"; then
-      ac_aux_dir=$ac_dir
-      ac_install_sh="$ac_aux_dir/$ac_t -c"
-      break 2
-    fi
-  done
+  if test -f "$ac_dir/install-sh"; then
+    ac_aux_dir=$ac_dir
+    ac_install_sh="$ac_aux_dir/install-sh -c"
+    break
+  elif test -f "$ac_dir/install.sh"; then
+    ac_aux_dir=$ac_dir
+    ac_install_sh="$ac_aux_dir/install.sh -c"
+    break
+  elif test -f "$ac_dir/shtool"; then
+    ac_aux_dir=$ac_dir
+    ac_install_sh="$ac_aux_dir/shtool install -c"
+    break
+  fi
 done
 if test -z "$ac_aux_dir"; then
-  as_fn_error "cannot find install-sh, install.sh, or shtool in \"$srcdir\" \"$srcdir/..\" \"$srcdir/../..\"" "$LINENO" 5
+  as_fn_error $? "cannot find install-sh, install.sh, or shtool in \"$srcdir\" \"$srcdir/..\" \"$srcdir/../..\"" "$LINENO" 5
 fi
 
 # These three variables are undocumented and unsupported,
@@ -4461,7 +4453,7 @@
 
 # Make sure we can run config.sub.
 $SHELL "$ac_aux_dir/config.sub" sun4 >/dev/null 2>&1 ||
-  as_fn_error "cannot run $SHELL $ac_aux_dir/config.sub" "$LINENO" 5
+  as_fn_error $? "cannot run $SHELL $ac_aux_dir/config.sub" "$LINENO" 5
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking build system type" >&5
 $as_echo_n "checking build system type... " >&6; }
@@ -4472,16 +4464,16 @@
 test "x$ac_build_alias" = x &&
   ac_build_alias=`$SHELL "$ac_aux_dir/config.guess"`
 test "x$ac_build_alias" = x &&
-  as_fn_error "cannot guess build type; you must specify one" "$LINENO" 5
+  as_fn_error $? "cannot guess build type; you must specify one" "$LINENO" 5
 ac_cv_build=`$SHELL "$ac_aux_dir/config.sub" $ac_build_alias` ||
-  as_fn_error "$SHELL $ac_aux_dir/config.sub $ac_build_alias failed" "$LINENO" 5
+  as_fn_error $? "$SHELL $ac_aux_dir/config.sub $ac_build_alias failed" "$LINENO" 5
 
 fi
 { $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_build" >&5
 $as_echo "$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='-'
@@ -4506,7 +4498,7 @@
   ac_cv_host=$ac_cv_build
 else
   ac_cv_host=`$SHELL "$ac_aux_dir/config.sub" $host_alias` ||
-    as_fn_error "$SHELL $ac_aux_dir/config.sub $host_alias failed" "$LINENO" 5
+    as_fn_error $? "$SHELL $ac_aux_dir/config.sub $host_alias failed" "$LINENO" 5
 fi
 
 fi
@@ -4514,7 +4506,7 @@
 $as_echo "$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='-'
@@ -4539,7 +4531,7 @@
   ac_cv_target=$ac_cv_host
 else
   ac_cv_target=`$SHELL "$ac_aux_dir/config.sub" $target_alias` ||
-    as_fn_error "$SHELL $ac_aux_dir/config.sub $target_alias failed" "$LINENO" 5
+    as_fn_error $? "$SHELL $ac_aux_dir/config.sub $target_alias failed" "$LINENO" 5
 fi
 
 fi
@@ -4547,7 +4539,7 @@
 $as_echo "$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='-'
@@ -4570,17 +4562,64 @@
     NONENONEs,x,x, &&
   program_prefix=${target_alias}-
 
-PTHREAD_CFLAGS=
-PTHREAD_LDFLAGS=
-PTHREAD_LIBS=
-case "$host_os" in
-openbsd*)
-	PTHREAD_CFLAGS=-pthread
-	PTHREAD_LDFLAGS=-pthread
-	;;
-esac
+{ $as_echo "$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 :
+  $as_echo_n "(cached) " >&6
+else
+  ac_func_search_save_LIBS=$LIBS
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
 
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char sem_close ();
+int
+main ()
+{
+return sem_close ();
+  ;
+  return 0;
+}
+_ACEOF
+for ac_lib in '' pthread; do
+  if test -z "$ac_lib"; then
+    ac_res="none required"
+  else
+    ac_res=-l$ac_lib
+    LIBS="-l$ac_lib  $ac_func_search_save_LIBS"
+  fi
+  if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_search_sem_close=$ac_res
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext
+  if test "${ac_cv_search_sem_close+set}" = set; then :
+  break
+fi
+done
+if test "${ac_cv_search_sem_close+set}" = set; then :
 
+else
+  ac_cv_search_sem_close=no
+fi
+rm conftest.$ac_ext
+LIBS=$ac_func_search_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_search_sem_close" >&5
+$as_echo "$ac_cv_search_sem_close" >&6; }
+ac_res=$ac_cv_search_sem_close
+if test "$ac_res" != no; then :
+  test "$ac_res" = "none required" || LIBS="$ac_res $LIBS"
+  EXTRA_LIBS="$EXTRA_LIBS $ac_lib"
+else
+  { $as_echo "$as_me:${as_lineno-$LINENO}: Not found" >&5
+$as_echo "$as_me: Not found" >&6;}
+fi
 
 
 ac_config_files="$ac_config_files unix.buildinfo"
@@ -4669,6 +4708,7 @@
 
 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$//'
@@ -4830,19 +4870,19 @@
 (unset CDPATH) >/dev/null 2>&1 && unset CDPATH
 
 
-# as_fn_error ERROR [LINENO LOG_FD]
-# ---------------------------------
+# 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 $?, using 1 if that was 0.
+# script with STATUS, using 1 if that was 0.
 as_fn_error ()
 {
-  as_status=$?; test $as_status -eq 0 && as_status=1
-  if test "$3"; then
-    as_lineno=${as_lineno-"$2"} as_lineno_stack=as_lineno_stack=$as_lineno_stack
-    $as_echo "$as_me:${as_lineno-$LINENO}: error: $1" >&$3
+  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
+    $as_echo "$as_me:${as_lineno-$LINENO}: error: $2" >&$4
   fi
-  $as_echo "$as_me: error: $1" >&2
+  $as_echo "$as_me: error: $2" >&2
   as_fn_exit $as_status
 } # as_fn_error
 
@@ -5038,7 +5078,7 @@
       test -d "$as_dir" && break
     done
     test -z "$as_dirs" || eval "mkdir $as_dirs"
-  } || test -d "$as_dir" || as_fn_error "cannot create directory $as_dir"
+  } || test -d "$as_dir" || as_fn_error $? "cannot create directory $as_dir"
 
 
 } # as_fn_mkdir_p
@@ -5092,7 +5132,7 @@
 # values after options handling.
 ac_log="
 This file was extended by Haskell unix package $as_me 2.0, which was
-generated by GNU Autoconf 2.65.  Invocation command line was
+generated by GNU Autoconf 2.67.  Invocation command line was
 
   CONFIG_FILES    = $CONFIG_FILES
   CONFIG_HEADERS  = $CONFIG_HEADERS
@@ -5154,10 +5194,10 @@
 ac_cs_config="`$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 2.65,
+configured by $0, generated by GNU Autoconf 2.67,
   with options \\"\$ac_cs_config\\"
 
-Copyright (C) 2009 Free Software Foundation, Inc.
+Copyright (C) 2010 Free Software Foundation, Inc.
 This config.status script is free software; the Free Software Foundation
 gives unlimited permission to copy, distribute and modify it."
 
@@ -5172,11 +5212,16 @@
 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
@@ -5198,6 +5243,7 @@
     $ac_shift
     case $ac_optarg in
     *\'*) ac_optarg=`$as_echo "$ac_optarg" | sed "s/'/'\\\\\\\\''/g"` ;;
+    '') as_fn_error $? "missing file argument" ;;
     esac
     as_fn_append CONFIG_FILES " '$ac_optarg'"
     ac_need_defaults=false;;
@@ -5210,7 +5256,7 @@
     ac_need_defaults=false;;
   --he | --h)
     # Conflict between --help and --header
-    as_fn_error "ambiguous option: \`$1'
+    as_fn_error $? "ambiguous option: \`$1'
 Try \`$0 --help' for more information.";;
   --help | --hel | -h )
     $as_echo "$ac_cs_usage"; exit ;;
@@ -5219,7 +5265,7 @@
     ac_cs_silent=: ;;
 
   # This is an error.
-  -*) as_fn_error "unrecognized option: \`$1'
+  -*) as_fn_error $? "unrecognized option: \`$1'
 Try \`$0 --help' for more information." ;;
 
   *) as_fn_append ac_config_targets " $1"
@@ -5271,7 +5317,7 @@
     "include/HsUnixConfig.h") CONFIG_HEADERS="$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
 
@@ -5308,7 +5354,7 @@
 {
   tmp=./conf$$-$RANDOM
   (umask 077 && mkdir "$tmp")
-} || as_fn_error "cannot create a temporary directory in ." "$LINENO" 5
+} || as_fn_error $? "cannot create a temporary directory in ." "$LINENO" 5
 
 # Set up the scripts for CONFIG_FILES section.
 # No need to generate them if there are no CONFIG_FILES.
@@ -5325,7 +5371,7 @@
 fi
 ac_cs_awk_cr=`$AWK 'BEGIN { print "a\rb" }' </dev/null 2>/dev/null`
 if test "$ac_cs_awk_cr" = "a${ac_cr}b"; then
-  ac_cs_awk_cr='\r'
+  ac_cs_awk_cr='\\r'
 else
   ac_cs_awk_cr=$ac_cr
 fi
@@ -5339,18 +5385,18 @@
   echo "$ac_subst_vars" | sed 's/.*/&!$&$ac_delim/' &&
   echo "_ACEOF"
 } >conf$$subs.sh ||
-  as_fn_error "could not make $CONFIG_STATUS" "$LINENO" 5
-ac_delim_num=`echo "$ac_subst_vars" | grep -c '$'`
+  as_fn_error $? "could not make $CONFIG_STATUS" "$LINENO" 5
+ac_delim_num=`echo "$ac_subst_vars" | grep -c '^'`
 ac_delim='%!_!# '
 for ac_last_try in false false false false false :; do
   . ./conf$$subs.sh ||
-    as_fn_error "could not make $CONFIG_STATUS" "$LINENO" 5
+    as_fn_error $? "could not make $CONFIG_STATUS" "$LINENO" 5
 
   ac_delim_n=`sed -n "s/.*$ac_delim\$/X/p" conf$$subs.awk | grep -c X`
   if test $ac_delim_n = $ac_delim_num; then
     break
   elif $ac_last_try; then
-    as_fn_error "could not make $CONFIG_STATUS" "$LINENO" 5
+    as_fn_error $? "could not make $CONFIG_STATUS" "$LINENO" 5
   else
     ac_delim="$ac_delim!$ac_delim _$ac_delim!! "
   fi
@@ -5439,20 +5485,28 @@
 else
   cat
 fi < "$tmp/subs1.awk" > "$tmp/subs.awk" \
-  || as_fn_error "could not setup config files machinery" "$LINENO" 5
+  || as_fn_error $? "could not setup config files machinery" "$LINENO" 5
 _ACEOF
 
-# VPATH may cause trouble with some makes, so we remove $(srcdir),
-# ${srcdir} and @srcdir@ from VPATH if srcdir is ".", strip leading and
+# VPATH may cause trouble with some makes, so we remove sole $(srcdir),
+# ${srcdir} and @srcdir@ entries from VPATH if srcdir is ".", strip leading and
 # trailing colons and then remove the whole line if VPATH becomes empty
 # (actually we leave an empty line to preserve line numbers).
 if test "x$srcdir" = x.; then
-  ac_vpsub='/^[	 ]*VPATH[	 ]*=/{
-s/:*\$(srcdir):*/:/
-s/:*\${srcdir}:*/:/
-s/:*@srcdir@:*/:/
-s/^\([^=]*=[	 ]*\):*/\1/
+  ac_vpsub='/^[	 ]*VPATH[	 ]*=[	 ]*/{
+h
+s///
+s/^/:/
+s/[	 ]*$/:/
+s/:\$(srcdir):/:/g
+s/:\${srcdir}:/:/g
+s/:@srcdir@:/:/g
+s/^:*//
 s/:*$//
+x
+s/\(=[	 ]*\).*/\1/
+G
+s/\n//
 s/^[^=]*=[	 ]*$//
 }'
 fi
@@ -5480,7 +5534,7 @@
   if test -z "$ac_t"; then
     break
   elif $ac_last_try; then
-    as_fn_error "could not make $CONFIG_HEADERS" "$LINENO" 5
+    as_fn_error $? "could not make $CONFIG_HEADERS" "$LINENO" 5
   else
     ac_delim="$ac_delim!$ac_delim _$ac_delim!! "
   fi
@@ -5565,7 +5619,7 @@
 _ACAWK
 _ACEOF
 cat >>$CONFIG_STATUS <<\_ACEOF || ac_write_fail=1
-  as_fn_error "could not setup config headers machinery" "$LINENO" 5
+  as_fn_error $? "could not setup config headers machinery" "$LINENO" 5
 fi # test -n "$CONFIG_HEADERS"
 
 
@@ -5578,7 +5632,7 @@
   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:$ac_tag.in;;
   esac
@@ -5606,7 +5660,7 @@
 	   [\\/$]*) false;;
 	   *) test -f "$srcdir/$ac_f" && ac_f="$srcdir/$ac_f";;
 	   esac ||
-	   as_fn_error "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'"
@@ -5633,7 +5687,7 @@
 
     case $ac_tag in
     *:-:* | *:-) cat >"$tmp/stdin" \
-      || as_fn_error "could not create $ac_file" "$LINENO" 5 ;;
+      || as_fn_error $? "could not create $ac_file" "$LINENO" 5  ;;
     esac
     ;;
   esac
@@ -5759,22 +5813,22 @@
 $ac_datarootdir_hack
 "
 eval sed \"\$ac_sed_extra\" "$ac_file_inputs" | $AWK -f "$tmp/subs.awk" >$tmp/out \
-  || as_fn_error "could not create $ac_file" "$LINENO" 5
+  || 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"; } &&
   { $as_echo "$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
+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;}
+which seems to be undefined.  Please make sure it is defined" >&2;}
 
   rm -f "$tmp/stdin"
   case $ac_file in
   -) cat "$tmp/out" && rm -f "$tmp/out";;
   *) rm -f "$ac_file" && mv "$tmp/out" "$ac_file";;
   esac \
-  || as_fn_error "could not create $ac_file" "$LINENO" 5
+  || as_fn_error $? "could not create $ac_file" "$LINENO" 5
  ;;
   :H)
   #
@@ -5785,19 +5839,19 @@
       $as_echo "/* $configure_input  */" \
       && eval '$AWK -f "$tmp/defines.awk"' "$ac_file_inputs"
     } >"$tmp/config.h" \
-      || as_fn_error "could not create $ac_file" "$LINENO" 5
+      || as_fn_error $? "could not create $ac_file" "$LINENO" 5
     if diff "$ac_file" "$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" \
-	|| as_fn_error "could not create $ac_file" "$LINENO" 5
+	|| 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" \
-      || as_fn_error "could not create -" "$LINENO" 5
+      || as_fn_error $? "could not create -" "$LINENO" 5
   fi
  ;;
 
@@ -5812,7 +5866,7 @@
 ac_clean_files=$ac_clean_files_save
 
 test $ac_write_fail = 0 ||
-  as_fn_error "write failure creating $CONFIG_STATUS" "$LINENO" 5
+  as_fn_error $? "write failure creating $CONFIG_STATUS" "$LINENO" 5
 
 
 # configure is writing to config.log, and then calls config.status.
@@ -5833,7 +5887,7 @@
   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 $?
+  $ac_cs_success || as_fn_exit 1
 fi
 if test -n "$ac_unrecognized_opts" && test "$enable_option_checking" != no; then
   { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: unrecognized options: $ac_unrecognized_opts" >&5
diff --git a/configure.ac b/configure.ac
--- a/configure.ac
+++ b/configure.ac
@@ -207,18 +207,9 @@
 # -{l,}pthread goo
 AC_CANONICAL_TARGET
 
-PTHREAD_CFLAGS=
-PTHREAD_LDFLAGS=
-PTHREAD_LIBS=
-case "$host_os" in
-openbsd*)
-	PTHREAD_CFLAGS=-pthread
-	PTHREAD_LDFLAGS=-pthread
-	;;
-esac
-AC_SUBST(PTHREAD_CFLAGS)
-AC_SUBST(PTHREAD_LDFLAGS)
-AC_SUBST(PTHREAD_LIBS)
+AC_SEARCH_LIBS(sem_close, pthread,
+    [EXTRA_LIBS="$EXTRA_LIBS $ac_lib"],
+    [AC_MSG_NOTICE([Not found])])
 
 AC_CONFIG_FILES([unix.buildinfo])
 
diff --git a/include/HsUnixConfig.h b/include/HsUnixConfig.h
--- a/include/HsUnixConfig.h
+++ b/include/HsUnixConfig.h
@@ -284,7 +284,7 @@
 /* #undef USLEEP_RETURNS_VOID */
 
 /* Number of bits in a file offset, on hosts where this is settable. */
-#define _FILE_OFFSET_BITS 64
+/* #undef _FILE_OFFSET_BITS */
 
 /* Define for large files, on AIX-style hosts. */
 /* #undef _LARGE_FILES */
diff --git a/unix.buildinfo.in b/unix.buildinfo.in
--- a/unix.buildinfo.in
+++ b/unix.buildinfo.in
@@ -1,4 +1,2 @@
 buildable: @BUILD_PACKAGE_BOOL@
-cc-options: @PTHREAD_CFLAGS@
-ld-options: @PTHREAD_LDFLAGS@
-extra-libraries: @EXTRA_LIBS@ @PTHREAD_LIBS@
+extra-libraries: @EXTRA_LIBS@
diff --git a/unix.cabal b/unix.cabal
--- a/unix.cabal
+++ b/unix.cabal
@@ -1,5 +1,5 @@
 name:		unix
-version:	2.4.1.0
+version:	2.4.2.0
 license:	BSD3
 license-file:	LICENSE
 maintainer:	libraries@haskell.org