diff --git a/music/os2_m.c b/music/os2_m.c
--- a/music/os2_m.c
+++ b/music/os2_m.c
@@ -1,3 +1,5 @@
+/* $Id$ */
+
 #include "stdafx.h"
 #include "openttd.h"
 #include "music/os2_m.h"