2012-02-17  Benjamin Kosnik  <bkoz@redhat.com>

        PR libstdc++/51798 continued.
        * acinclude.m4 (GLIBCXX_ENABLE_ATOMIC_BUILTINS): Grep for
        __atomic_, not __sync.


diff --git a/libstdc++-v3/acinclude.m4 b/libstdc++-v3/acinclude.m4
index 46a5532..b832527 100644
--- a/libstdc++-v3/acinclude.m4
+++ b/libstdc++-v3/acinclude.m4
@@ -2824,7 +2824,7 @@ EOF
 
     AC_MSG_CHECKING([for atomic builtins for bool])
     if AC_TRY_EVAL(ac_compile); then
-      if grep __sync_ conftest.s >/dev/null 2>&1 ; then
+      if grep __atomic_ conftest.s >/dev/null 2>&1 ; then
 	glibcxx_cv_atomic_bool=no
       else
 	glibcxx_cv_atomic_bool=yes
@@ -2853,7 +2853,7 @@ EOF
 
     AC_MSG_CHECKING([for atomic builtins for short])
     if AC_TRY_EVAL(ac_compile); then
-      if grep __sync_ conftest.s >/dev/null 2>&1 ; then
+      if grep __atomic_ conftest.s >/dev/null 2>&1 ; then
 	glibcxx_cv_atomic_short=no
       else
 	glibcxx_cv_atomic_short=yes
@@ -2883,7 +2883,7 @@ EOF
 
     AC_MSG_CHECKING([for atomic builtins for int])
     if AC_TRY_EVAL(ac_compile); then
-      if grep __sync_ conftest.s >/dev/null 2>&1 ; then
+      if grep __atomic_ conftest.s >/dev/null 2>&1 ; then
 	glibcxx_cv_atomic_int=no
       else
 	glibcxx_cv_atomic_int=yes
@@ -2912,7 +2912,7 @@ EOF
 
     AC_MSG_CHECKING([for atomic builtins for long long])
     if AC_TRY_EVAL(ac_compile); then
-      if grep __sync_ conftest.s >/dev/null 2>&1 ; then
+      if grep __atomic_ conftest.s >/dev/null 2>&1 ; then
 	glibcxx_cv_atomic_long_long=no
       else
 	glibcxx_cv_atomic_long_long=yes