diff -up chromium-64.0.3282.119/third_party/ffmpeg/libavutil/cpu.c.ffmpeg-stdatomic chromium-64.0.3282.119/third_party/ffmpeg/libavutil/cpu.c
--- chromium-64.0.3282.119/third_party/ffmpeg/libavutil/cpu.c.ffmpeg-stdatomic	2018-01-25 11:55:57.880936815 -0500
+++ chromium-64.0.3282.119/third_party/ffmpeg/libavutil/cpu.c	2018-01-25 11:57:18.456787888 -0500
@@ -18,7 +18,13 @@
 
 #include <stddef.h>
 #include <stdint.h>
+// GCC 4.8 didn't have stdatomic, but was advertising it.
+// https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58016
+#if !defined(__clang__) && defined(__GNUC__) && (__GNUC__ == 4 || (__GNUC__ == 4 && (__GNUC_MINOR__ == 8)))
+#include <compat/atomics/gcc/stdatomic.h>
+#else
 #include <stdatomic.h>
+#endif
 
 #include "attributes.h"
 #include "cpu.h"