diff --git a/tests/sys/aio/Makefile b/tests/sys/aio/Makefile
index 972059c57c1..851252def34 100644
--- a/tests/sys/aio/Makefile
+++ b/tests/sys/aio/Makefile
@@ -9,6 +9,8 @@ ATF_TESTS_C+=	aio_test
 DPADD.aio_test+=	${LIBUTIL}
 LDADD.aio_test+=	-lutil
 
+CFLAGS+=	-I${.CURDIR:H:H}
+
 WARNS?=	6
 
 .include <bsd.test.mk>