diff -ruN /usr/ports/cad/openvsp/Makefile cad/openvsp/Makefile
--- /usr/ports/cad/openvsp/Makefile	2017-07-27 15:41:31.000000000 +0200
+++ cad/openvsp/Makefile	2017-07-28 20:28:42.607425000 +0200
@@ -3,6 +3,7 @@
 
 PORTNAME=	openvsp
 PORTVERSION=	3.13.0
+PORTREVISION=	1
 DISTVERSIONPREFIX=	${GH_PROJECT}_
 CATEGORIES=	cad
 
@@ -34,6 +35,14 @@
 CMAKE_INSTALL_PREFIX=	${STAGEDIR}${PREFIX}
 USES=		cmake:outsource,noninja compiler:gcc-c++11-lib jpeg
 
+# On FreeBSD < 11 libc++ lacks support for sized delete operators.
+# GCC dropped the builtin version of these operators in 6+ by
+# defaulting to gnu++14. Force c++11 instead.
+# For a more detailed discussion see:
+# https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=219484
+
+USE_CXXSTD=	gnu++11
+
 CMAKE_ARGS=	-DVSP_USE_SYSTEM_CMINPACK:BOOLEAN=yes \
 		-DVSP_USE_SYSTEM_CPPTEST:BOOLEAN=yes \
 		-DVSP_USE_SYSTEM_CODEELI:BOOLEAN=no \