lavu: test for broken binutils on ARM

Some old gnu assemblers fail to assemble qdadd correctly
Ideally we should check this at build time, but better to
check at run time than mysteriously failing.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavutil/utils.c

@@ -35,6 +35,11 @@ unsigned avutil_version(void)
     av_assert0(LIBAVUTIL_VERSION_MICRO >= 100);
     av_assert0(HAVE_MMX2 == HAVE_MMXEXT);
 
+    if (av_sat_dadd32(1, 2) != 5) {
+        av_log(NULL, AV_LOG_FATAL, "Libavutil has been build with a broken binutils, please upgrade binutils and rebuild\n");
+        abort();
+    }
+
     return LIBAVUTIL_VERSION_INT;
 }