* macosx/tclMacOSXNotify.c (Tcl_InitNotifier, Tcl_WaitForEvent): create

	notifier thread lazily upon first call to Tcl_WaitForEvent() rather than
	in Tcl_InitNotifier(). Allows calling exeve() in processes where the
	event loop has not yet been run (Darwin's execve() fails in processes
	with more than one thread), in particular allows embedders to call
	fork() followed by execve(), previously the pthread_atfork() child
	handler's call to Tcl_InitNotifier() would immediately recreate the
	notifier thread in the child after a fork.

	* macosx/tclMacOSXNotify.c (Tcl_InitNotifier):     add support for
	* unix/tclUnixFCmd.c (DoRenameFile, CopyFileAtts): weakly importing
	* unix/tclUnixInit.c (TclpSetInitialEncodings):    symbols not available
	on OSX 10.2 or 10.3, enables binaires built on later OSX versions to run
	on earlier ones.
	* macosx/README: document how to enable weak-linking; cleanup.
	* unix/tclUnixPort.h: add support for weak-linking; conditionalize
	AvailabilityMacros.h inclusion; only disable realpath on 10.2 or earlier
	when threads are enabled.
	* unix/tclLoadDyld.c (TclpLoadMemoryGetBuffer): change runtime Darwin
	* unix/tclUnixInit.c (TclpInitPlatform):        release check to use
	                                                global initialized once.
	* unix/tclUnixFCmd.c (DoRenameFile, TclpObjNormalizePath): add runtime
	Darwin release check to determine if realpath is threadsafe.
	* unix/configure.in: add check on Darwin for compiler support of weak
	* unix/tcl.m4:       import and for AvailabilityMacros.h header; move
	Darwin specific checks & defines that are only relevant to the tcl build
	out of tcl.m4; restrict framework option to Darwin; cleanup quoting.
	* unix/configure: autoconf-2.13

	* unix/tclLoadDyld.c (TclpLoadMemory):
	* unix/tclUnixPipe.c (TclpCreateProcess): fix signed-with-unsigned
	comparison and other warnings from gcc4 -Wextra.

1 files changed, 23 insertions, 11 deletions

diff --git a/macosx/README b/macosx/README
index 46469cb..2475ea2 100644
--- a/macosx/README
+++ b/macosx/README
@@ -1,7 +1,7 @@
 Tcl Mac OS X README 
 -----------------
 
-RCS: @(#) $Id: README,v 1.1.2.4 2005/11/27 02:34:41 das Exp $
+RCS: @(#) $Id: README,v 1.1.2.5 2006/07/20 06:21:41 das Exp $
 
 This is the README file for the Mac OS X/Darwin version of Tcl.
 
@@ -36,9 +36,12 @@ Mac OS X specific bugs should usually be assigned to 'das' or 'wolfsuit'.
 - At a minimum, Mac OS X 10.1 is required to run Tcl, but OS X 10.3 or higher is
 recommended (certain [file] operations behave incorrectly on earlier releases).
 
-- Tcl built on Mac OS X 10.x will not run on 10.y for y < x, on the other hand
-Tcl built on 10.y will run on 10.x for y < x (but without any of the fixes and
-optimizations that would be available in a binary built on 10.x).
+- Unless weak-linking is used, Tcl built on Mac OS X 10.x will not run on 10.y
+with y < x; on the other hand Tcl built on 10.y will always run on 10.x with
+y <= x (but without any of the fixes and optimizations that would be available
+in a binary built on 10.x).
+Weak-linking is available on OS X 10.2 or later, it additionally allows Tcl
+built on 10.x to run on any 10.y with x > y >= z (for a chosen z >= 2).
 
 - Tcl extensions can be installed in any of:
 	$HOME/Library/Tcl /Library/Tcl /Network/Library/Tcl /System/Library/Tcl
@@ -79,10 +82,9 @@ http://connect.apple.com (after you register for free ADC membership).
 (see below for details), but can also be built with the standard unix configure
 and make buildsystem in tcl/unix as on any other unix platform (indeed, the
 Makefile is just a wrapper around the unix buildsystem).
-The Mac OS X specifc configure flags are --enable-framework and
+The Mac OS X specific configure flags are --enable-framework and
 --disable-corefoundation (which disables CF and notably reverts to the standard
-select based notifier, you will only need this if your require use of naked fork
-(i.e. not followed by execve) in an unthreaded core).
+select based notifier).
 
 - It is also possible to build with Apple's IDE via the tcl/macosx/Tcl.pbproj
 project, this simply calls through to the tcl/macosx/GNUMakefile.
@@ -91,12 +93,22 @@ project, this simply calls through to the tcl/macosx/GNUMakefile.
     export CFLAGS="-arch ppc -arch ppc64 -arch i386 \
 	-isysroot /Developer/SDKs/MacOSX10.4u.sdk -mmacosx-version-min=10.4"
 This requires Mac OS X 10.4 and Xcode 2.2 (_not_ Xcode 2.1) and will work on any
-of the architectures (on i386 DTKs, the -isysroot is not required). Note that it
-is not possible to configure correctly if the current architecture is not
+of the architectures (on intel Macs, the -isysroot is not required). Note that
+it is not possible to configure correctly if the current architecture is not
 present in CFLAGS (i.e. -arch `arch` must always be there). Universal builds of
 Tcl TEA extensions are also possible with CFLAGS set as above, they will be
 [load]able by universal as well as thin binaries of Tcl.
 
+- To enable weak-linking, set the MACOSX_DEPLOYMENT_TARGET environment variable
+to the minimal OS version (>= 10.2) the binaries should be able to run on, e.g:
+    export MACOSX_DEPLOYMENT_TARGET=10.2
+This requires Mac OS X 10.2 and gcc 3.1; if you have gcc 4 or later you can set
+CFLAGS instead:
+    export CFLAGS="-mmacosx-version-min=10.2"
+The Tcl.xcodeproj is setup to produce binaires that can run on 10.2 or later,
+except for the 'ReleaseUniversal'configuration, where they require 10.4.
+Support for weak-linking was added to the code for 8.4.14/8.5a5.
+
 Detailed Instructions for building with macosx/Makefile
 -------------------------------------------------------
 
@@ -127,8 +139,8 @@ instead by passing an INSTALL_ROOT argument to make:
 - The default Makefile targets will build _both_ debug and optimized versions of
 the Tcl framework with the standard convention of naming the debug library
 Tcl.framework/Tcl_debug.
-This allows you to dynamically link to the debug libraries at runtime by setting
-	setenv DYLD_IMAGE_SUFFIX _debug
+This allows switching to the debug libraries at runtime by setting
+	export DYLD_IMAGE_SUFFIX=_debug
 (c.f. man dyld for more details)
 
 If you only want to build and install the debug or optimized build, use the