Index: head/devel/bison/Makefile
===================================================================
--- head/devel/bison/Makefile	(revision 523820)
+++ head/devel/bison/Makefile	(revision 523821)
@@ -1,41 +1,41 @@
 # Created by: Jerry Hicks
 # $FreeBSD$
 
 PORTNAME=	bison
 PORTVERSION=	3.5.1
 PORTEPOCH=	1
 CATEGORIES=	devel
 MASTER_SITES=	GNU
 
 MAINTAINER=	sunpoet@FreeBSD.org
 COMMENT=	Parser generator from FSF, (mostly) compatible with Yacc
 
 LICENSE=	GPLv3+
 LICENSE_FILE=	${WRKSRC}/COPYING
 
 BUILD_DEPENDS=	${RUN_DEPENDS}
 RUN_DEPENDS=	m4>=1.4.16,1:devel/m4
 
 OPTIONS_DEFINE=	DOCS EXAMPLES NLS
 OPTIONS_SUB=	yes
 
-USES=		charsetfix localbase makeinfo perl5 tar:xz
+USES=		charsetfix compiler:c11 localbase makeinfo perl5 tar:xz
 USE_PERL5=	build
 
 CONFIGURE_ARGS=	--disable-yacc --enable-relocatable
 GNU_CONFIGURE=	yes
 LIBS+=		-lm
 TEST_TARGET=	check
 
 INFO=		bison
 
 NLS_CONFIGURE_ENABLE=	nls
 NLS_CONFIGURE_OFF=	ac_cv_libtextstyle=no
 NLS_LIB_DEPENDS=	libtextstyle.so:devel/libtextstyle
 NLS_USES=		gettext
 
 post-patch:
 	@${REINPLACE_CMD} -e 's|$$(docdir)\(/examples\)|$$(datarootdir)\1/bison|' ${WRKSRC}/Makefile.in
 	@${GREP} -l '_Noreturn void' ${WRKSRC}/lib/*.[ch] | ${XARGS} -J % ${REINPLACE_CMD} -e 's|\(.*\) _Noreturn void|_Noreturn \1 void|' %
 
 .include <bsd.port.mk>