commit 1dc922cdd0798d5522331f1c98657f494d18c6b9
Author: Derek Buitenhuis <derek.buitenhuis@gmail.com>
Date:   Sun Dec 27 18:37:59 2015 -0500

    track: Wrap C headers in extern "C" properly
    
    This fixes av_rescale being undefiend during linking with some
    GCC versions (e.g. 4.8.4 on Ubuntu 14.04).
    
    Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>

diff --git a/src/core/track.cpp b/src/core/track.cpp
index 136bc21..23e57ad 100644
--- a/src/core/track.cpp
+++ b/src/core/track.cpp
@@ -25,9 +25,11 @@
 
 #include <algorithm>
 
+extern "C" {
 #include <libavutil/avutil.h>
 #include <libavutil/common.h>
 #include <libavutil/mathematics.h>
+}
 
 namespace {
 FrameInfo ReadFrame(ZipFile &stream, FrameInfo const& prev, const FFMS_TrackType TT) {