diff --git a/devel/flatbuffers205/Makefile b/devel/flatbuffers205/Makefile
index 1610ec4044ed..514f362243db 100644
--- a/devel/flatbuffers205/Makefile
+++ b/devel/flatbuffers205/Makefile
@@ -1,27 +1,33 @@
 PORTNAME=	flatbuffers
 DISTVERSIONPREFIX=	v
 DISTVERSION=	2.0.5
 CATEGORIES=	devel
 PKGNAMESUFFIX=	205
 
 MAINTAINER=	yuri@FreeBSD.org
 COMMENT=	Memory efficient serialization library
 WWW=		https://google.github.io/flatbuffers/
 
 LICENSE=	APACHE20
 LICENSE_FILE=	${WRKSRC}/LICENSE.txt
 
 USES=		cmake:testing compiler:c++11-lib cpe python:build
 CPE_VENDOR=	google
 USE_LDCONFIG=	yes
 
 USE_GITHUB=	yes
 GH_ACCOUNT=	google
 
 CMAKE_ON=	FLATBUFFERS_BUILD_SHAREDLIB
 CMAKE_OFF=	FLATBUFFERS_BUILD_FLATLIB FLATBUFFERS_BUILD_TESTS
 CMAKE_TESTING_ON=	FLATBUFFERS_BUILD_TESTS # one test fails, see https://github.com/google/flatbuffers/issues/7009
 
 BINARY_ALIAS=	git=false python3=${PYTHON_CMD}
 
+.include <bsd.port.options.mk>
+
+.if ${OPSYS} == FreeBSD && ( ${OSVERSION} >= 1400091 || ( ${OSVERSION} >= 1302507 && ${OSVERSION} < 1400000 ))
+CXXFLAGS+=	-Wno-error=unused-command-line-argument
+.endif
+
 .include <bsd.port.mk>