diff --git a/ChangeLog b/ChangeLog
index dbf183a..252caa3 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2007-01-23  Bruno Haible  <bruno@clisp.org>
+
+	Allow 64-bit builds on MacOS X 10.5.
+	* m4/general.m4 (CL_CANONICAL_HOST_CPU): Test for x86_64 CPU if
+	"uname -m" returns "i386".
+	Reported by Ron Garret <ron@flownet.com>.
+
 2007-01-20  Bruno Haible  <bruno@clisp.org>
 
 	Avoid some gcc warnings.
diff --git a/m4/general.m4 b/m4/general.m4
index d0ce215..b573e38 100644
--- a/m4/general.m4
+++ b/m4/general.m4
@@ -1,4 +1,4 @@
-dnl Copyright (C) 1993-2006 Free Software Foundation, Inc.
+dnl Copyright (C) 1993-2008 Free Software Foundation, Inc.
 dnl This file is free software, distributed under the terms of the GNU
 dnl General Public License.  As a special exception to the GNU General
 dnl Public License, this file may be distributed as part of a program
@@ -184,9 +184,11 @@ else
   host_cpu=sparc
 fi
     ;;
+dnl MacOS X 10.5 machines on x86_64 platforms have 'uname -m' = "i386" even
+dnl if 64-bit programs are fully supported.
 dnl AMD64 running Linux have 'uname -m' = "x86_64" even if userland is purely
 dnl 32-bit.
-  x86_64 )
+  i386 | x86_64 )
     AC_CACHE_CHECK([for 64-bit userland on x86-64], cl_cv_host_x86_64, [
 AC_COMPILE_IFELSE([AC_LANG_PROGRAM(
 [[#if !defined __x86_64__