diff --git a/math/libpoly/Makefile b/math/libpoly/Makefile
index 5f19e5aa3520..09cb3a214f0b 100644
--- a/math/libpoly/Makefile
+++ b/math/libpoly/Makefile
@@ -1,22 +1,28 @@
 PORTNAME=	libpoly
 DISTVERSIONPREFIX=	v
 DISTVERSION=	0.1.11
 CATEGORIES=	math
 
 MAINTAINER=	yuri@FreeBSD.org
 COMMENT=	C library for manipulating polynomials
 WWW=		https://github.com/SRI-CSL/libpoly
 
 LICENSE=	GPLv3
 LICENSE_FILE=	${WRKSRC}/LICENCE
 
 LIB_DEPENDS=	libgmp.so:math/gmp
 
 USES=		cmake:testing
 USE_GITHUB=	yes
 GH_ACCOUNT=	SRI-CSL
 USE_LDCONFIG=	yes
 
 CMAKE_OFF=	LIBPOLY_BUILD_PYTHON_API LIBPOLY_BUILD_STATIC LIBPOLY_BUILD_STATIC_PIC
 
-.include <bsd.port.mk>
+.include <bsd.port.pre.mk>
+
+.if ${OPSYS} == FreeBSD && ${OSVERSION} >= 1400079
+CFLAGS+=       -Wno-error=unused-but-set-variable
+.endif
+
+.include <bsd.port.post.mk>