--- firefox-42.0.orig/dom/media/webm/WebMDemuxer.cpp	2015-10-29 23:17:57.000000000 +0100
+++ firefox-42.0/dom/media/webm/WebMDemuxer.cpp	2015-12-08 05:28:13.471186350 +0100
@@ -17,6 +17,7 @@
 #include "nsAutoRef.h"
 #include "NesteggPacketHolder.h"
 #include "XiphExtradata.h"
+#include "prprf.h"
 
 #include <algorithm>
 #include <stdint.h>