Temporarily address gcc 4.7 breakage.

Change-Id: I8ebb2d5df2f8f8aedf252c94ff69505e61ed0a74
diff --git a/linker/linker_format.cpp b/linker/linker_format.cpp
index 60b759b..65c6264 100644
--- a/linker/linker_format.cpp
+++ b/linker/linker_format.cpp
@@ -26,6 +26,10 @@
  * SUCH DAMAGE.
  */
 
+// Temporarily disable _FORTIFY_SOURCE to get this code to
+// compile under GCC 4.7
+#undef _FORTIFY_SOURCE
+
 #include <assert.h>
 #include <stdarg.h>
 #include <string.h>