--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/components/desktop/firefox/patches/firefox31-gnu-130-xopen.patch	Mon Jan 11 09:27:45 2016 -0800
@@ -0,0 +1,14 @@
+Prevent:
+error: #error "Compiler or options invalid for pre-UNIX 03 X/Open applications  and pre-2001 POSIX applications
+
+--- mozilla-esr31/media/libpng/pngpriv.h.orig	2015-06-04 13:00:52.516503541 -0700
++++ mozilla-esr31/media/libpng/pngpriv.h	2015-06-04 13:00:52.515657420 -0700
+@@ -39,6 +39,8 @@
+  */
+ #define _POSIX_SOURCE 1 /* Just the POSIX 1003.1 and C89 APIs */
+ 
++#define _XOPEN_SOURCE 600
++
+ #ifndef PNG_VERSION_INFO_ONLY
+ /* Standard library headers not required by png.h: */
+ #  include <stdlib.h>