Index: head/math/librdata/Makefile
===================================================================
--- head/math/librdata/Makefile	(revision 555632)
+++ head/math/librdata/Makefile	(revision 555633)
@@ -1,23 +1,23 @@
 # Created by: Po-Chuan Hsieh <sunpoet@FreeBSD.org>
 # $FreeBSD$
 
 PORTNAME=	librdata
 PORTVERSION=	0.1.0.g20200911
 CATEGORIES=	math
 
 MAINTAINER=	sunpoet@FreeBSD.org
 COMMENT=	Read and write R data frames from C
 
 LICENSE=	MIT
 LICENSE_FILE=	${WRKSRC}/LICENSE
 
-USES=		autoreconf libtool gettext-tools
+USES=		autoreconf compiler:c11 libtool gettext-tools
 
 USE_GITHUB=	yes
 GH_ACCOUNT=	WizardMac
 GH_TAGNAME=	7188fa5
 
 GNU_CONFIGURE=	yes
 INSTALL_TARGET=	install-strip
 
 .include <bsd.port.mk>