diff --git a/sys/modules/geom/geom_uzip/Makefile b/sys/modules/geom/geom_uzip/Makefile
index 8e468451773..3efeb809527 100644
--- a/sys/modules/geom/geom_uzip/Makefile
+++ b/sys/modules/geom/geom_uzip/Makefile
@@ -4,6 +4,6 @@
 
 KMOD=	geom_uzip
 SRCS=	g_uzip.c
-#CFLAGS=	-g
+#CFLAGS=	-g -DINVARIANT_SUPPORT -DINVARIANTS
 
 .include <bsd.kmod.mk>