diff --git a/src/sound/null_s.h b/src/sound/null_s.h
--- a/src/sound/null_s.h
+++ b/src/sound/null_s.h
@@ -7,4 +7,4 @@
 
 extern const HalSoundDriver _null_sound_driver;
 
-#endif
+#endif /* SOUND_NULL_H */