Index: head/math/libxlsxwriter/Makefile
===================================================================
--- head/math/libxlsxwriter/Makefile	(revision 518674)
+++ head/math/libxlsxwriter/Makefile	(revision 518675)
@@ -1,24 +1,24 @@
 # $FreeBSD$
 
 PORTNAME=	libxlsxwriter
 PORTVERSION=	0.8.8
 DISTVERSIONPREFIX=	RELEASE_
 CATEGORIES=	math devel
 
 MAINTAINER=	bapt@FreeBSD.org
 COMMENT=	C library for creating Excel XLSX files
 
 LICENSE=	BSD2CLAUSE
 
 USE_GITHUB=	yes
 GH_ACCOUNT=	jmcnamara
 MAKE_ARGS=	INSTALL_DIR=${STAGEDIR}${PREFIX}
 
 USE_LDCONFIG=	yes
-USES=		gmake
+USES=		compiler:c11 gmake
 
 post-install:
 	${STRIP_CMD} ${STAGEDIR}${PREFIX}/lib/libxlsxwriter.so.0
 	${LN} -s libxlsxwriter.so.0 ${STAGEDIR}${PREFIX}/lib/libxlsxwriter.so
 
 .include <bsd.port.mk>