diff --git a/sys/modules/sound/driver/Makefile.inc b/sys/modules/sound/driver/Makefile.inc
index 124bfc8bd11a..63bf7601dc36 100644
--- a/sys/modules/sound/driver/Makefile.inc
+++ b/sys/modules/sound/driver/Makefile.inc
@@ -1,5 +1,5 @@
 # $FreeBSD$
 
-SRCS		+= ac97_if.h channel_if.h feeder_if.h mixer_if.h
+SRCS+=	ac97_if.h channel_if.h feeder_if.h mixer_if.h
 
 .include "../Makefile.inc"