Index: head/audio/caps-lv2/Makefile
===================================================================
--- head/audio/caps-lv2/Makefile	(revision 490350)
+++ head/audio/caps-lv2/Makefile	(revision 490351)
@@ -1,33 +1,38 @@
 # Created by: Yuri Victorovich <yuri@rawbw.com>
 # $FreeBSD$
 
 PORTNAME=	caps-lv2
 PORTVERSION=	g20170626
 PORTREVISION=	1
 CATEGORIES=	audio
 
 MAINTAINER=	yuri@FreeBSD.org
 COMMENT=	LV2 version of the C* Audio Plugin Suite
 
 LICENSE=	GPLv3
 LICENSE_FILE=	${WRKSRC}/COPYING
 
 BUILD_DEPENDS=	lv2>0:audio/lv2
 
 USES=		gmake localbase
 USE_GITHUB=	yes
 GH_ACCOUNT=	moddevices
 GH_TAGNAME=	072e2fe
 
 # It suffers from the regression in clang-6: https://bugs.llvm.org/show_bug.cgi?id=36916
 LLVM_VER=	50
 BUILD_DEPENDS+=	clang${LLVM_VER}:devel/llvm${LLVM_VER}
 CPP=		clang-cpp${LLVM_VER}
 CC=		clang${LLVM_VER}
 CXX=		clang++${LLVM_VER}
 
+.if exists(/usr/lib/libstdc++.so)
+CXXFLAGS+=	-stdlib=libstdc++
+LDFLAGS+=	-stdlib=libstdc++
+.endif
+
 post-patch:
 	@${REINPLACE_CMD} -e "s|__APPLE__|__FreeBSD__|" \
 		${WRKSRC}/dsp/v4f_IIR2.h
 
 .include <bsd.port.mk>