sync changelog with gcc, plus commit the following patch:

2010-06-09  Iain Sandoe  <iains@gcc.gnu.org>

	PR bootstrap/43170
	* tls.m4 (GCC_CHECK_TLS): Add volatile qualifier to the test
	references.  Move the main () test reference ahead of
	pthread_create().  Add a comment to explain the requirements
	of the test.

config/ChangeLog

@@ -1,25 +1,35 @@
+2010-06-09  Iain Sandoe  <iains@gcc.gnu.org>
+
+	PR bootstrap/43170
+	* tls.m4 (GCC_CHECK_TLS): Add volatile qualifier to the test 
+	references.  Move the main () test reference ahead of 
+	pthread_create().  Add a comment to explain the requirements
+	of the test.
+
 2010-06-03  Joern Rennecke <joern.rennecke@embecosm.com>
-            Ralf Wildenhues  <Ralf.Wildenhues@gmx.de>
+	    Ralf Wildenhues  <Ralf.Wildenhues@gmx.de>
 
-	Sync from GCC:
 	PR bootstrap/42798
 	* override.m4 (_AC_CHECK_DECL_BODY, _AC_CHECK_DECLS): Import
 	definitions from git Autoconf.
 
-2010-06-01  Ralf Wildenhues  <Ralf.Wildenhues@gmx.de>
-
-	Sync from GCC:
+2010-04-13  Steve Ellcey  <sje@cup.hp.com>
 
-	2010-04-13  Steve Ellcey  <sje@cup.hp.com>
 	* elf.m4: Add hppa[12]*-*-hpux* to list of non-elf platforms.
 
-	2010-01-05  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
+2010-03-23  Kai Tietz  <kai.tietz@onevision.com>
+
+	* mh-mingw: Revert accidentally checking r156315.
+
+2010-01-05  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>
+
 	* stdint.m4 (GCC_HEADER_STDINT): Don't typedef uint8_t etc. if
 	corresponding macros already exist.
 
-2010-02-15  Nick Clifton  <nickc@redhat.com>
+2010-01-02  Richard Guenther  <rguenther@suse.de>
 
-	* elf.m4: Import from gcc mainline.
+	PR lto/41529
+	* elf.m4: New file.
 
 2009-11-30  Joseph Myers  <joseph@codesourcery.com>
 

config/tls.m4

@@ -38,11 +38,16 @@ AC_DEFUN([GCC_CHECK_TLS], [
 	CFLAGS="$chktls_save_CFLAGS"
 	if test "X$thread_CFLAGS" != Xfailed; then
 	  CFLAGS="$thread_CFLAGS $chktls_save_CFLAGS"
+ 	  dnl Test for an old glibc bug that violated the __thread property.
+	  dnl Use volatile to ensure the compiler won't optimize away pointer
+	  dnl accesses it might otherwise assume to be redundant, or reorder 
+	  dnl them and reuse storage, which might lead to them pointing to
+	  dnl the same location.
 	  AC_RUN_IFELSE(
 	    [AC_LANG_PROGRAM(
 	       [#include <pthread.h>
 		__thread int a;
-		static int *a_in_other_thread;
+		static int *volatile a_in_other_thread;
 		static void *
 		thread_func (void *arg)
 		{
@@ -51,11 +56,11 @@ AC_DEFUN([GCC_CHECK_TLS], [
 		}],
 	       [pthread_t thread;
 		void *thread_retval;
-		int *a_in_main_thread;
+		int *volatile a_in_main_thread;
+		a_in_main_thread = &a;
 		if (pthread_create (&thread, (pthread_attr_t *)0,
 				    thread_func, (void *)0))
 		  return 0;
-		a_in_main_thread = &a;
 		if (pthread_join (thread, &thread_retval))
 		  return 0;
 		return (a_in_other_thread == a_in_main_thread);])],