diff --git a/devel/rubygem-atomic/Makefile b/devel/rubygem-atomic/Makefile
index 087896ade2ca..c90dc22f5518 100644
--- a/devel/rubygem-atomic/Makefile
+++ b/devel/rubygem-atomic/Makefile
@@ -1,15 +1,21 @@
 PORTNAME=	atomic
 PORTVERSION=	1.1.101
 CATEGORIES=	devel rubygems
 MASTER_SITES=	RG
 
 MAINTAINER=	ruby@FreeBSD.org
 COMMENT=	Atomic reference implementation
 WWW=		https://github.com/ruby-concurrency/atomic
 
 LICENSE=	APACHE20
 LICENSE_FILE=	${WRKSRC}/LICENSE
 
 USES=		gem
 
+.include <bsd.port.options.mk>
+
+.if ${OPSYS} == FreeBSD && ( ${OSVERSION} >= 1400079 || ( ${OSVERSION} >= 1302505 && ${OSVERSION} < 1400000 ))
+CONFIGURE_ARGS+=	--with-cflags="-Wno-error=int-conversion"
+.endif
+
 .include <bsd.port.mk>