diff --git a/sbin/hastctl/Makefile b/sbin/hastctl/Makefile
index b0aba704529a..af946a20ecaa 100644
--- a/sbin/hastctl/Makefile
+++ b/sbin/hastctl/Makefile
@@ -28,6 +28,7 @@ CFLAGS+=-DINET6
 .endif
 # This is needed to have WARNS > 1.
 CFLAGS+=-DYY_NO_UNPUT
+CFLAGS+=-DYY_NO_INPUT
 
 DPADD=	${LIBL} ${LIBUTIL}
 LDADD=	-ll -lutil