Index: head/mail/s-nail/Makefile
===================================================================
--- head/mail/s-nail/Makefile	(revision 523063)
+++ head/mail/s-nail/Makefile	(revision 523064)
@@ -1,45 +1,45 @@
 # $FreeBSD$
 
 PORTNAME=	s-nail
 PORTVERSION=	14.9.16
 CATEGORIES=	mail
 MASTER_SITES=	https://www.sdaoden.eu/downloads/
 
 MAINTAINER=	yasu@utahime.org
 COMMENT=	Send and receive Internet mail
 
 LICENSE=		BSD3CLAUSE BSD4CLAUSE ISCL MIT RFC2104 RSA
 LICENSE_COMB=		multi
 LICENSE_NAME_RFC2104=	License of RFC2104
 LICENSE_NAME_RSA=	RSA Data Security license
 LICENSE_FILE=		${WRKSRC}/COPYING
 LICENSE_PERMS_RFC2104=	dist-mirror dist-sell pkg-mirror pkg-sell auto-accept
 LICENSE_PERMS_RSA=	dist-mirror dist-sell pkg-mirror pkg-sell auto-accept
 
 LIB_DEPENDS=	libidn2.so:dns/libidn2
 RUN_DEPENDS=	mime-support>0:misc/mime-support
 
-USES=		iconv localbase ssl tar:xz
+USES=		compiler:c11 iconv localbase ssl tar:xz
 
 PLIST_FILES=	bin/s-nail \
 		"@sample etc/s-nail.rc.sample" \
 		libexec/s-nail-dotlock \
 		man/man1/s-nail.1.gz
 
 MAKEFILE=	makefile
 MAKE_ENV=	EXTRA_CFLAGS="-DLIBICONV_PLUG" INCS=-I${LOCALBASE}/include \
 		VAL_PREFIX=${PREFIX} VAL_MANDIR=${MANPREFIX}/man VAL_MIME_TYPES_SYS=${PREFIX}/etc/mime.types VAL_IDNA=idn2
 MAKE_JOBS_UNSAFE=	yes
 
 PORTDOCS=	NEWS README
 
 OPTIONS_DEFINE=	DOCS
 
 post-install:
 	${INSTALL_DATA} ${WRKSRC}/nail.rc ${STAGEDIR}${PREFIX}/etc/s-nail.rc.sample
 
 post-install-DOCS-on:
 	@${MKDIR} ${STAGEDIR}${DOCSDIR}
 	${INSTALL_DATA} ${PORTDOCS:S|^|${WRKSRC}/|} ${STAGEDIR}${DOCSDIR}
 
 .include <bsd.port.mk>