diff --git a/math/rubygem-rb-gsl/Makefile b/math/rubygem-rb-gsl/Makefile
index 2eb3167a140b..42139435c5ab 100644
--- a/math/rubygem-rb-gsl/Makefile
+++ b/math/rubygem-rb-gsl/Makefile
@@ -1,25 +1,25 @@
 PORTNAME=	gsl
 PORTVERSION=	2.1.0.2
 PORTREVISION=	5
 CATEGORIES=	math rubygems
 MASTER_SITES=	RG
 PKGNAMEPREFIX=	rubygem-rb-
 
 MAINTAINER=	murashin@gfd-dennou.org
 COMMENT=	Ruby extension library for GSL (GNU Scientific Library)
 WWW=		https://github.com/blackwinter/rb-gsl
 
 LICENSE=	GPLv2
 
 LIB_DEPENDS=	libgsl.so:math/gsl
 RUN_DEPENDS=	rubygem-narray>=0.5.9:math/rubygem-narray
 
 USES=		gem
 
 .include <bsd.port.options.mk>
 
 .if ${OPSYS} == FreeBSD && ( ${OSVERSION} >= 1400079 || ( ${OSVERSION} >= 1302505 && ${OSVERSION} < 1400000 ))
-CONFIGURE_ARGS+=	--with-cflags="-Wno-error=int-conversion"
+CONFIGURE_ARGS+=	--with-cflags="-Wno-error=int-conversion -Wno-error=incompatible-function-pointer-types"
 .endif
 
 .include <bsd.port.mk>