--- cad/openvsp/Makefile	2017-07-27 15:41:31.000000000 +0200
+++ cad/openvsp/Makefile	2017-07-27 21:02:25.825553000 +0200
@@ -34,6 +34,17 @@ 
 CMAKE_INSTALL_PREFIX=	${STAGEDIR}${PREFIX}
 USES=		cmake:outsource,noninja compiler:gcc-c++11-lib jpeg
 
+.include <bsd.port.pre.mk>
+
+# On FreeBSD < 11 libc++ lacks support for sized delete operators.
+# GCC dropped the builtin version of these operators in 6+
+# For a more detailed discussion see:
+# https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=219484
+
+.if ${OSVERSION} < 1100000
+USE_GCC=	5
+.endif
+
 CMAKE_ARGS=	-DVSP_USE_SYSTEM_CMINPACK:BOOLEAN=yes \
 		-DVSP_USE_SYSTEM_CPPTEST:BOOLEAN=yes \
 		-DVSP_USE_SYSTEM_CODEELI:BOOLEAN=no \
@@ -61,4 +72,4 @@ 
 .endfor
 	${CP} ${BUILD_WRKSRC}/${BUILD_PREFIX}/LICENSE ${STAGEDIR}${DATADIR}
 
-.include <bsd.port.mk>
+.include <bsd.port.post.mk>