--- mozilla-release.orig/js/src/jscpucfg.cpp	2011-07-08 03:15:24.000000000 +0200
+++ mozilla-release/js/src/jscpucfg.cpp	2013-02-08 09:41:16.000000000 +0100
@@ -177,6 +177,11 @@ int main(int argc, char **argv)
 
     printf("#endif /* js_cpucfg___ */\n");
 
+#if defined __GNUC__ && defined __x86_64__
+    printf("#define HAVE_VA_LIST_AS_ARRAY\n");
+    printf("\n");
+#endif
+
     return EXIT_SUCCESS;
 }