diff --git a/graphics/box/Makefile b/graphics/box/Makefile
index 9d8c5ce8d318..fc77b3f31a8d 100644
--- a/graphics/box/Makefile
+++ b/graphics/box/Makefile
@@ -31,6 +31,8 @@ PLIST_SUB=	PLIST_VER=${PORTVERSION:R}
 
 OPTIONS_DEFINE=	DOCS EXAMPLES
 
+CFLAGS+=	-Wno-error=incompatible-function-pointer-types
+
 post-patch:
 	${TOUCH} ${WRKSRC}/man/${PORTNAME}.sgml