* macosx/tclMacOSXNotify.c: implemented pthread_atfork() handler that

	* unix/tcl.m4 (Darwin):     recreates CoreFoundation state and notifier
	thread in the child after a fork(). Note that pthread_atfork() is
	available starting with Tiger only. Because vfork() is used by the core
	on Darwin, [exec]/[open] are not affected by this fix, only extensions
	or embedders that call fork() directly (such as TclX). However, this
	only makes fork() safe from corefoundation tcl with --disable-threads;
	as on all platforms, forked children may deadlock in threaded tcl due to
	the potential for stale locked mutexes in the child. [Patch 923072]
	* unix/configure: autoconf-2.59
	* unix/tclConfig.h.in: autoheader-2.59

5 files changed, 309 insertions, 78 deletions

diff --git a/ChangeLog b/ChangeLog
index f9117d9..1165dae 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+2006-05-27  Daniel Steffen  <das@users.sourceforge.net>
+
+	* macosx/tclMacOSXNotify.c: implemented pthread_atfork() handler that
+	* unix/tcl.m4 (Darwin):     recreates CoreFoundation state and notifier
+	thread in the child after a fork(). Note that pthread_atfork() is
+	available starting with Tiger only. Because vfork() is used by the core
+	on Darwin, [exec]/[open] are not affected by this fix, only extensions
+	or embedders that call fork() directly (such as TclX). However, this
+	only makes fork() safe from corefoundation tcl with --disable-threads;
+	as on all platforms, forked children may deadlock in threaded tcl due to
+	the potential for stale locked mutexes in the child. [Patch 923072]
+	* unix/configure: autoconf-2.59
+	* unix/tclConfig.h.in: autoheader-2.59
+
 2006-05-24  Donal K. Fellows  <donal.k.fellows@manchester.ac.uk>
 
 	* unix/tcl.m4 (SC_CONFIG_SYSTEM): Fixed quoting of command script to
diff --git a/macosx/tclMacOSXNotify.c b/macosx/tclMacOSXNotify.c
index a5e9627..a99e11b 100644
--- a/macosx/tclMacOSXNotify.c
+++ b/macosx/tclMacOSXNotify.c
@@ -8,12 +8,12 @@
  * Copyright (c) 1995-1997 Sun Microsystems, Inc.
  * Copyright 2001, Apple Computer, Inc.
  * Copyright (c) 2005 Tcl Core Team.
- * Copyright (c) 2005 Daniel A. Steffen <das@users.sourceforge.net>
+ * Copyright (c) 2005-2006 Daniel A. Steffen <das@users.sourceforge.net>
  *
  * See the file "license.terms" for information on usage and redistribution of
  * this file, and for a DISCLAIMER OF ALL WARRANTIES.
  *
- * RCS: @(#) $Id: tclMacOSXNotify.c,v 1.6 2005/11/27 02:33:49 das Exp $
+ * RCS: @(#) $Id: tclMacOSXNotify.c,v 1.7 2006/05/27 05:22:58 das Exp $
  */
 
 #include "tclInt.h"
@@ -216,6 +216,13 @@ static pthread_t notifierThread;
 
 static void	NotifierThreadProc(ClientData clientData);
 static int	FileHandlerEventProc(Tcl_Event *evPtr, int flags);
+
+#ifdef HAVE_PTHREAD_ATFORK
+static int	atForkInit = 0;
+static void	AtForkPrepare(void);
+static void	AtForkParent(void);
+static void	AtForkChild(void);
+#endif
 
 /*
  *----------------------------------------------------------------------
@@ -225,7 +232,7 @@ static int	FileHandlerEventProc(Tcl_Event *evPtr, int flags);
  *	Initializes the platform specific notifier state.
  *
  * Results:
- *	Returns a handle to the notifier state for this thread..
+ *	Returns a handle to the notifier state for this thread.
  *
  * Side effects:
  *	None.
@@ -265,6 +272,20 @@ Tcl_InitNotifier(void)
      */
 
     LOCK_NOTIFIER_INIT;
+#ifdef HAVE_PTHREAD_ATFORK
+    /*
+     * Install pthread_atfork handlers to reinstall the notifier thread in the
+     * child of a fork.
+     */
+
+    if (!atForkInit) {
+	int result = pthread_atfork(AtForkPrepare, AtForkParent, AtForkChild);
+	if (result) { 
+	    Tcl_Panic("Tcl_InitNotifier: pthread_atfork failed");
+	}
+	atForkInit = 1;
+    }
+#endif
     if (notifierCount == 0) {
 	int fds[2], status, result;
 	pthread_attr_t attr;
@@ -1058,6 +1079,94 @@ NotifierThreadProc(
     }
     pthread_exit (0);
 }
+
+#ifdef HAVE_PTHREAD_ATFORK
+/*
+ *----------------------------------------------------------------------
+ *
+ * AtForkPrepare --
+ *
+ *	Lock the notifier in preparation for a fork.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+AtForkPrepare(void)
+{
+    LOCK_NOTIFIER_INIT;
+    LOCK_NOTIFIER;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * AtForkParent --
+ *
+ *	Unlock the notifier in the parent after a fork.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+AtForkParent(void)
+{
+    UNLOCK_NOTIFIER;
+    UNLOCK_NOTIFIER_INIT;
+}
+
+/*
+ *----------------------------------------------------------------------
+ *
+ * AtForkChild --
+ *
+ *	Unlock and reinstall the notifier in the child after a fork.
+ *
+ * Results:
+ *	None.
+ *
+ * Side effects:
+ *	None.
+ *
+ *----------------------------------------------------------------------
+ */
+
+static void
+AtForkChild(void)
+{
+    ThreadSpecificData *tsdPtr = TCL_TSD_INIT(&dataKey);
+
+    UNLOCK_NOTIFIER;
+    UNLOCK_NOTIFIER_INIT;
+    if (tsdPtr->runLoop) {
+	tsdPtr->runLoop = NULL;
+	CFRunLoopSourceInvalidate(tsdPtr->runLoopSource);
+	CFRelease(tsdPtr->runLoopSource);
+	tsdPtr->runLoopSource = NULL;
+    }
+    if (notifierCount > 0) {
+	notifierCount = 0;
+	/* Note that Tcl_FinalizeNotifier does not use its clientData
+	 * parameter, so discard return value of Tcl_InitNotifier here and
+	 * leave stale clientData in tclNotify.c's ThreadSpecificData.
+	 */
+	Tcl_InitNotifier();
+    }
+}
+#endif /* HAVE_PTHREAD_ATFORK */
+
 #endif /* HAVE_COREFOUNDATION */
 
 /*
diff --git a/unix/configure b/unix/configure
index 4b8a6ea..3731800 100755
--- a/unix/configure
+++ b/unix/configure
@@ -7194,8 +7194,8 @@ echo "${ECHO_T}$tcl_cv_ld_elf" >&6
 	    CFLAGS_OPTIMIZE="-Os"
 	    SHLIB_CFLAGS="-fno-common"
 	    if test $do64bit = yes; then
-	        do64bit_ok=yes
-	        CFLAGS="$CFLAGS -arch ppc64 -mpowerpc64 -mcpu=G5"
+		do64bit_ok=yes
+		CFLAGS="$CFLAGS -arch ppc64 -mpowerpc64 -mcpu=G5"
 	    fi
 	    SHLIB_LD='${CC} -dynamiclib ${CFLAGS} ${LDFLAGS}'
 	    echo "$as_me:$LINENO: checking if ld accepts -single_module flag" >&5
@@ -7204,9 +7204,9 @@ if test "${tcl_cv_ld_single_module+set}" = set; then
   echo $ECHO_N "(cached) $ECHO_C" >&6
 else
 
-	        hold_ldflags=$LDFLAGS
-	        LDFLAGS="$LDFLAGS -dynamiclib -Wl,-single_module"
-	        cat >conftest.$ac_ext <<_ACEOF
+		hold_ldflags=$LDFLAGS
+		LDFLAGS="$LDFLAGS -dynamiclib -Wl,-single_module"
+		cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
 cat confdefs.h >>conftest.$ac_ext
@@ -7252,12 +7252,12 @@ tcl_cv_ld_single_module=no
 fi
 rm -f conftest.err conftest.$ac_objext \
       conftest$ac_exeext conftest.$ac_ext
-	        LDFLAGS=$hold_ldflags
+		LDFLAGS=$hold_ldflags
 fi
 echo "$as_me:$LINENO: result: $tcl_cv_ld_single_module" >&5
 echo "${ECHO_T}$tcl_cv_ld_single_module" >&6
 	    if test $tcl_cv_ld_single_module = yes; then
-	        SHLIB_LD="${SHLIB_LD} -Wl,-single_module"
+		SHLIB_LD="${SHLIB_LD} -Wl,-single_module"
 	    fi
 	    SHLIB_LD_LIBS='${LIBS}'
 	    SHLIB_SUFFIX=".dylib"
@@ -7274,9 +7274,9 @@ if test "${tcl_cv_ld_search_paths_first+set}" = set; then
   echo $ECHO_N "(cached) $ECHO_C" >&6
 else
 
-	        hold_ldflags=$LDFLAGS
-	        LDFLAGS="$LDFLAGS -Wl,-search_paths_first"
-	        cat >conftest.$ac_ext <<_ACEOF
+		hold_ldflags=$LDFLAGS
+		LDFLAGS="$LDFLAGS -Wl,-search_paths_first"
+		cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
 cat confdefs.h >>conftest.$ac_ext
@@ -7322,45 +7322,45 @@ tcl_cv_ld_search_paths_first=no
 fi
 rm -f conftest.err conftest.$ac_objext \
       conftest$ac_exeext conftest.$ac_ext
-	        LDFLAGS=$hold_ldflags
+		LDFLAGS=$hold_ldflags
 fi
 echo "$as_me:$LINENO: result: $tcl_cv_ld_search_paths_first" >&5
 echo "${ECHO_T}$tcl_cv_ld_search_paths_first" >&6
 	    if test $tcl_cv_ld_search_paths_first = yes; then
-	        LDFLAGS="$LDFLAGS -Wl,-search_paths_first"
+		LDFLAGS="$LDFLAGS -Wl,-search_paths_first"
 	    fi
 	    CC_SEARCH_FLAGS=""
 	    LD_SEARCH_FLAGS=""
 	    LD_LIBRARY_PATH_VAR="DYLD_LIBRARY_PATH"
 	    PLAT_OBJS='${MAC_OSX_OBJS}'
 	    PLAT_SRCS='${MAC_OSX_SRCS}'
-            echo "$as_me:$LINENO: checking whether to use CoreFoundation" >&5
+	    echo "$as_me:$LINENO: checking whether to use CoreFoundation" >&5
 echo $ECHO_N "checking whether to use CoreFoundation... $ECHO_C" >&6
-            # Check whether --enable-corefoundation or --disable-corefoundation was given.
+	    # Check whether --enable-corefoundation or --disable-corefoundation was given.
 if test "${enable_corefoundation+set}" = set; then
   enableval="$enable_corefoundation"
   tcl_corefoundation=$enableval
 else
   tcl_corefoundation=yes
 fi;
-            echo "$as_me:$LINENO: result: $tcl_corefoundation" >&5
+	    echo "$as_me:$LINENO: result: $tcl_corefoundation" >&5
 echo "${ECHO_T}$tcl_corefoundation" >&6
-            if test $tcl_corefoundation = yes; then
-                echo "$as_me:$LINENO: checking for CoreFoundation.framework" >&5
+	    if test $tcl_corefoundation = yes; then
+		echo "$as_me:$LINENO: checking for CoreFoundation.framework" >&5
 echo $ECHO_N "checking for CoreFoundation.framework... $ECHO_C" >&6
 if test "${tcl_cv_lib_corefoundation+set}" = set; then
   echo $ECHO_N "(cached) $ECHO_C" >&6
 else
 
-                    hold_libs=$LIBS; hold_cflags=$CFLAGS
-                    if test $do64bit_ok = no ; then
-                        # remove -arch ppc64 from CFLAGS while testing presence
-                        # of CF, otherwise all archs will have CF disabled.
-                        # CF for ppc64 is disabled in tclUnixPort.h instead.
-                        CFLAGS="`echo "$CFLAGS" | sed -e 's/-arch ppc64/-arch ppc/'`"
-                    fi
-                    LIBS="$LIBS -framework CoreFoundation"
-                    cat >conftest.$ac_ext <<_ACEOF
+		    hold_libs=$LIBS; hold_cflags=$CFLAGS
+		    if test $do64bit_ok = no ; then
+			# remove -arch ppc64 from CFLAGS while testing presence
+			# of CF, otherwise all archs will have CF disabled.
+			# CF for ppc64 is disabled in tclUnixPort.h instead.
+			CFLAGS="`echo "$CFLAGS" | sed -e 's/-arch ppc64/-arch ppc/'`"
+		    fi
+		    LIBS="$LIBS -framework CoreFoundation"
+		    cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
 cat confdefs.h >>conftest.$ac_ext
@@ -7406,19 +7406,17 @@ tcl_cv_lib_corefoundation=no
 fi
 rm -f conftest.err conftest.$ac_objext \
       conftest$ac_exeext conftest.$ac_ext
-                    LIBS=$hold_libs; CFLAGS=$hold_cflags
+		    LIBS=$hold_libs; CFLAGS=$hold_cflags
 fi
 echo "$as_me:$LINENO: result: $tcl_cv_lib_corefoundation" >&5
 echo "${ECHO_T}$tcl_cv_lib_corefoundation" >&6
-                if test $tcl_cv_lib_corefoundation = yes; then
-                    LIBS="$LIBS -framework CoreFoundation"
+		if test $tcl_cv_lib_corefoundation = yes; then
+		    LIBS="$LIBS -framework CoreFoundation"
 
 cat >>confdefs.h <<\_ACEOF
 #define HAVE_COREFOUNDATION 1
 _ACEOF
 
-                fi
-	    fi
 
 for ac_header in libkern/OSAtomic.h
 do
@@ -7672,6 +7670,110 @@ fi
 done
 
 
+for ac_func in pthread_atfork
+do
+as_ac_var=`echo "ac_cv_func_$ac_func" | $as_tr_sh`
+echo "$as_me:$LINENO: checking for $ac_func" >&5
+echo $ECHO_N "checking for $ac_func... $ECHO_C" >&6
+if eval "test \"\${$as_ac_var+set}\" = set"; then
+  echo $ECHO_N "(cached) $ECHO_C" >&6
+else
+  cat >conftest.$ac_ext <<_ACEOF
+/* confdefs.h.  */
+_ACEOF
+cat confdefs.h >>conftest.$ac_ext
+cat >>conftest.$ac_ext <<_ACEOF
+/* end confdefs.h.  */
+/* Define $ac_func to an innocuous variant, in case <limits.h> declares $ac_func.
+   For example, HP-UX 11i <limits.h> declares gettimeofday.  */
+#define $ac_func innocuous_$ac_func
+
+/* System header to define __stub macros and hopefully few prototypes,
+    which can conflict with char $ac_func (); below.
+    Prefer <limits.h> to <assert.h> if __STDC__ is defined, since
+    <limits.h> exists even on freestanding compilers.  */
+
+#ifdef __STDC__
+# include <limits.h>
+#else
+# include <assert.h>
+#endif
+
+#undef $ac_func
+
+/* Override any gcc2 internal prototype to avoid an error.  */
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+/* We use char because int might match the return type of a gcc2
+   builtin and then its argument prototype would still apply.  */
+char $ac_func ();
+/* The GNU C library defines this for functions which it implements
+    to always fail with ENOSYS.  Some functions are actually named
+    something starting with __ and the normal name is an alias.  */
+#if defined (__stub_$ac_func) || defined (__stub___$ac_func)
+choke me
+#else
+char (*f) () = $ac_func;
+#endif
+#ifdef __cplusplus
+}
+#endif
+
+int
+main ()
+{
+return f != $ac_func;
+  ;
+  return 0;
+}
+_ACEOF
+rm -f conftest.$ac_objext conftest$ac_exeext
+if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
+  (eval $ac_link) 2>conftest.er1
+  ac_status=$?
+  grep -v '^ *+' conftest.er1 >conftest.err
+  rm -f conftest.er1
+  cat conftest.err >&5
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); } &&
+	 { ac_try='test -z "$ac_c_werror_flag"
+			 || test ! -s conftest.err'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; } &&
+	 { ac_try='test -s conftest$ac_exeext'
+  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
+  (eval $ac_try) 2>&5
+  ac_status=$?
+  echo "$as_me:$LINENO: \$? = $ac_status" >&5
+  (exit $ac_status); }; }; then
+  eval "$as_ac_var=yes"
+else
+  echo "$as_me: failed program was:" >&5
+sed 's/^/| /' conftest.$ac_ext >&5
+
+eval "$as_ac_var=no"
+fi
+rm -f conftest.err conftest.$ac_objext \
+      conftest$ac_exeext conftest.$ac_ext
+fi
+echo "$as_me:$LINENO: result: `eval echo '${'$as_ac_var'}'`" >&5
+echo "${ECHO_T}`eval echo '${'$as_ac_var'}'`" >&6
+if test `eval echo '${'$as_ac_var'}'` = yes; then
+  cat >>confdefs.h <<_ACEOF
+#define `echo "HAVE_$ac_func" | $as_tr_cpp` 1
+_ACEOF
+
+fi
+done
+
+		fi
+	    fi
+
 for ac_header in copyfile.h
 do
 as_ac_Header=`echo "ac_cv_header_$ac_header" | $as_tr_sh`
@@ -8042,8 +8144,8 @@ echo "$as_me:$LINENO: result: $ac_cv_func_realpath" >&5
 echo "${ECHO_T}$ac_cv_func_realpath" >&6
 
 	    if test $ac_cv_func_realpath = yes -a "${TCL_THREADS}" = 1 \
-	            -a `uname -r | awk -F. '{print $1}'` -lt 7 ; then
-	        ac_cv_func_realpath=no
+		    -a `uname -r | awk -F. '{print $1}'` -lt 7 ; then
+		ac_cv_func_realpath=no
 	    fi
 	    ;;
 	NEXTSTEP-*)
diff --git a/unix/tcl.m4 b/unix/tcl.m4
index 11197a9..3b2e228 100644
--- a/unix/tcl.m4
+++ b/unix/tcl.m4
@@ -1559,17 +1559,17 @@ dnl AC_CHECK_TOOL(AR, ar)
 	    CFLAGS_OPTIMIZE="-Os"
 	    SHLIB_CFLAGS="-fno-common"
 	    if test $do64bit = yes; then
-	        do64bit_ok=yes
-	        CFLAGS="$CFLAGS -arch ppc64 -mpowerpc64 -mcpu=G5"
+		do64bit_ok=yes
+		CFLAGS="$CFLAGS -arch ppc64 -mpowerpc64 -mcpu=G5"
 	    fi
 	    SHLIB_LD='${CC} -dynamiclib ${CFLAGS} ${LDFLAGS}'
 	    AC_CACHE_CHECK([if ld accepts -single_module flag], tcl_cv_ld_single_module, [
-	        hold_ldflags=$LDFLAGS
-	        LDFLAGS="$LDFLAGS -dynamiclib -Wl,-single_module"
-	        AC_TRY_LINK(, [int i;], tcl_cv_ld_single_module=yes, tcl_cv_ld_single_module=no)
-	        LDFLAGS=$hold_ldflags])
+		hold_ldflags=$LDFLAGS
+		LDFLAGS="$LDFLAGS -dynamiclib -Wl,-single_module"
+		AC_TRY_LINK(, [int i;], tcl_cv_ld_single_module=yes, tcl_cv_ld_single_module=no)
+		LDFLAGS=$hold_ldflags])
 	    if test $tcl_cv_ld_single_module = yes; then
-	        SHLIB_LD="${SHLIB_LD} -Wl,-single_module"
+		SHLIB_LD="${SHLIB_LD} -Wl,-single_module"
 	    fi
 	    SHLIB_LD_LIBS='${LIBS}'
 	    SHLIB_SUFFIX=".dylib"
@@ -1581,60 +1581,63 @@ dnl AC_CHECK_TOOL(AR, ar)
 		LDFLAGS="$LDFLAGS -prebind"
 	    LDFLAGS="$LDFLAGS -headerpad_max_install_names"
 	    AC_CACHE_CHECK([if ld accepts -search_paths_first flag], tcl_cv_ld_search_paths_first, [
-	        hold_ldflags=$LDFLAGS
-	        LDFLAGS="$LDFLAGS -Wl,-search_paths_first"
-	        AC_TRY_LINK(, [int i;], tcl_cv_ld_search_paths_first=yes, tcl_cv_ld_search_paths_first=no)
-	        LDFLAGS=$hold_ldflags])
+		hold_ldflags=$LDFLAGS
+		LDFLAGS="$LDFLAGS -Wl,-search_paths_first"
+		AC_TRY_LINK(, [int i;], tcl_cv_ld_search_paths_first=yes, tcl_cv_ld_search_paths_first=no)
+		LDFLAGS=$hold_ldflags])
 	    if test $tcl_cv_ld_search_paths_first = yes; then
-	        LDFLAGS="$LDFLAGS -Wl,-search_paths_first"
+		LDFLAGS="$LDFLAGS -Wl,-search_paths_first"
 	    fi
 	    CC_SEARCH_FLAGS=""
 	    LD_SEARCH_FLAGS=""
 	    LD_LIBRARY_PATH_VAR="DYLD_LIBRARY_PATH"
 	    PLAT_OBJS='${MAC_OSX_OBJS}'
 	    PLAT_SRCS='${MAC_OSX_SRCS}'
-            AC_MSG_CHECKING([whether to use CoreFoundation])
-            AC_ARG_ENABLE(corefoundation,
+	    AC_MSG_CHECKING([whether to use CoreFoundation])
+	    AC_ARG_ENABLE(corefoundation,
 		AC_HELP_STRING([--enable-corefoundation],
 		    [use CoreFoundation API on MacOSX (default: yes)]),
-                [tcl_corefoundation=$enableval], [tcl_corefoundation=yes])
-            AC_MSG_RESULT([$tcl_corefoundation])
-            if test $tcl_corefoundation = yes; then
-                AC_CACHE_CHECK([for CoreFoundation.framework], tcl_cv_lib_corefoundation, [
-                    hold_libs=$LIBS; hold_cflags=$CFLAGS
-                    if test $do64bit_ok = no ; then
-                        # remove -arch ppc64 from CFLAGS while testing presence
-                        # of CF, otherwise all archs will have CF disabled.
-                        # CF for ppc64 is disabled in tclUnixPort.h instead.
-                        CFLAGS="`echo "$CFLAGS" | sed -e 's/-arch ppc64/-arch ppc/'`"
-                    fi
-                    LIBS="$LIBS -framework CoreFoundation"
-                    AC_TRY_LINK([#include <CoreFoundation/CoreFoundation.h>], 
-                        [CFBundleRef b = CFBundleGetMainBundle();], 
-                        tcl_cv_lib_corefoundation=yes, tcl_cv_lib_corefoundation=no)
-                    LIBS=$hold_libs; CFLAGS=$hold_cflags])
-                if test $tcl_cv_lib_corefoundation = yes; then
-                    LIBS="$LIBS -framework CoreFoundation"
-                    AC_DEFINE(HAVE_COREFOUNDATION, 1, 
-                        [Do we have access to Darwin CoreFoundation.framework ?])
-                fi
+		[tcl_corefoundation=$enableval], [tcl_corefoundation=yes])
+	    AC_MSG_RESULT([$tcl_corefoundation])
+	    if test $tcl_corefoundation = yes; then
+		AC_CACHE_CHECK([for CoreFoundation.framework], tcl_cv_lib_corefoundation, [
+		    hold_libs=$LIBS; hold_cflags=$CFLAGS
+		    if test $do64bit_ok = no ; then
+			# remove -arch ppc64 from CFLAGS while testing presence
+			# of CF, otherwise all archs will have CF disabled.
+			# CF for ppc64 is disabled in tclUnixPort.h instead.
+			CFLAGS="`echo "$CFLAGS" | sed -e 's/-arch ppc64/-arch ppc/'`"
+		    fi
+		    LIBS="$LIBS -framework CoreFoundation"
+		    AC_TRY_LINK([#include <CoreFoundation/CoreFoundation.h>], 
+			[CFBundleRef b = CFBundleGetMainBundle();], 
+			tcl_cv_lib_corefoundation=yes, tcl_cv_lib_corefoundation=no)
+		    LIBS=$hold_libs; CFLAGS=$hold_cflags])
+		if test $tcl_cv_lib_corefoundation = yes; then
+		    LIBS="$LIBS -framework CoreFoundation"
+		    AC_DEFINE(HAVE_COREFOUNDATION, 1, 
+			[Do we have access to Darwin CoreFoundation.framework ?])
+		    AC_CHECK_HEADERS(libkern/OSAtomic.h)
+		    AC_CHECK_FUNCS(OSSpinLockLock)
+		    AC_CHECK_FUNCS(pthread_atfork)
+		fi
 	    fi
-	    AC_CHECK_HEADERS(libkern/OSAtomic.h)
-	    AC_CHECK_FUNCS(OSSpinLockLock)
 	    AC_CHECK_HEADERS(copyfile.h)
 	    AC_CHECK_FUNCS(copyfile)
 	    AC_DEFINE(MAC_OSX_TCL, 1, [Is this a Mac I see before me?])
 	    AC_DEFINE(USE_VFORK, 1, [Should we use vfork() instead of fork()?])
-	    AC_DEFINE(TCL_DEFAULT_ENCODING,"utf-8",
+	    AC_DEFINE(TCL_DEFAULT_ENCODING, "utf-8",
 		[Are we to override what our default encoding is?])
-	    AC_DEFINE(MODULE_SCOPE, __private_extern__, [Linker support for module scope symbols])
-	    AC_DEFINE(TCL_LOAD_FROM_MEMORY, 1, [Can this platform load code from memory?])
+	    AC_DEFINE(MODULE_SCOPE, __private_extern__,
+		[Linker support for module scope symbols])
+	    AC_DEFINE(TCL_LOAD_FROM_MEMORY, 1,
+		[Can this platform load code from memory?])
 	    # prior to Darwin 7, realpath is not threadsafe, so don't
 	    # use it when threads are enabled, c.f. bug # 711232:
 	    AC_CHECK_FUNC(realpath)
 	    if test $ac_cv_func_realpath = yes -a "${TCL_THREADS}" = 1 \
-	            -a `uname -r | awk -F. '{print [$]1}'` -lt 7 ; then
-	        ac_cv_func_realpath=no
+		    -a `uname -r | awk -F. '{print [$]1}'` -lt 7 ; then
+		ac_cv_func_realpath=no
 	    fi
 	    ;;
 	NEXTSTEP-*)
diff --git a/unix/tclConfig.h.in b/unix/tclConfig.h.in
index 348dedb..2e3d21f 100644
--- a/unix/tclConfig.h.in
+++ b/unix/tclConfig.h.in
@@ -76,6 +76,9 @@
 /* Define to 1 if you have the `OSSpinLockLock' function. */
 #undef HAVE_OSSPINLOCKLOCK
 
+/* Define to 1 if you have the `pthread_atfork' function. */
+#undef HAVE_PTHREAD_ATFORK
+
 /* Do we want a BSD-like thread-attribute interface? */
 #undef HAVE_PTHREAD_ATTR_GET_NP