diff --git a/media/ffvpx/libavutil_visibility.h b/media/ffvpx/libavutil_visibility.h
index a5cce0844a..706aacdf32 100644
--- a/media/ffvpx/libavutil_visibility.h
+++ b/media/ffvpx/libavutil_visibility.h
@@ -9,6 +9,15 @@
 #ifndef MOZILLA_AVUTIL_VISIBILITY_H
 #define MOZILLA_AVUTIL_VISIBILITY_H
 
+// We need to preemptively include <stdlib.h> before anyone[1] has a chance
+// to include <limits.h>. We do this to avoid a Linux clang build error, in
+// -ffreestanding mode, which happens when limits.h defines MB_LEN_MAX to some
+// value that is different from what stdlib.h expects. If we include stdlib.h
+// before limits.h, then they don't get a chance to interact badly.
+//
+// [1] (e.g. libavutil/common.h, which is indirectly included by log.h below.)
+#include <stdlib.h>
+
 #pragma GCC visibility push(default)
 #include "libavutil/cpu.h"