package/libglib2: fix compilation issue on SPARC

Fixes http://autobuild.buildroot.net/results/b3c/b3cb6515496cf09d305a1077d01f87d75ece8a8d/

Patch added to improve detection of atomic support in the compiler.

Signed-off-by: Brendan Heading <brendanheading@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/libglib2/0001-fix-compile-time-atomic-detection.patch

@@ -0,0 +1,28 @@
+[PATCH] Fix compilation issues on architectures with limited atomic support
+
+Improved compile-time detection of atomic support in the compiler.
+
+Upstream-Status: submitted
+See : https://bugzilla.gnome.org/show_bug.cgi?id=752731
+
+Signed-off-by: Brendan Heading <brendanheading@gmail.com>
+---
+ glib/gthread-posix.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/glib/gthread-posix.c b/glib/gthread-posix.c
+index ae5d805..8db8557 100644
+--- a/glib/gthread-posix.c
++++ b/glib/gthread-posix.c
+@@ -67,7 +67,7 @@
+ #endif
+ 
+ /* clang defines __ATOMIC_SEQ_CST but doesn't support the GCC extension */
+-#if defined(HAVE_FUTEX) && defined(__ATOMIC_SEQ_CST) && !defined(__clang__)
++#if defined(HAVE_FUTEX) && defined(__ATOMIC_SEQ_CST) && defined(__GCC_HAVE_SYNC_COMPARE_AND_SWAP_4) && !defined(__clang__)
+ #define USE_NATIVE_MUTEX
+ #endif
+ 
+-- 
+2.4.3
+