Fix for travis build issue

extern/osg-ffmpeg-videoplayer/videoplayer.hpp

@@ -1,6 +1,14 @@
 #ifndef VIDEOPLAYER_H
 #define VIDEOPLAYER_H
 
+// FIXME: This can't be right? The ffmpeg headers refuse to build without UINT64_C,
+// which only gets defined in stdint.h in either C99 mode or with this macro
+// defined...
+#ifndef __STDC_CONSTANT_MACROS
+#define __STDC_CONSTANT_MACROS
+#endif
+#include <stdint.h>
+
 #include <string>
 #include <memory>