phantomjs build failure system/compiler not supported.

[Johan Hendriks]

Hello I try to build grafana3 which has phantomjs as a dependency, but i
get a system compiler error.

root at desk:/usr/ports/lang/phantomjs # make
===>  Building for phantomjs-2.1.1
cd /usr/ports/lang/phantomjs/work/phantomjs-2.1.1 && /usr/bin/env CC=cc
CXX=c++ GMAKE=gmake OSTYPE=freebsd MAKEFLAGS=
PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin:/root/bin
/usr/local/bin/python2.7 build.py --jobs 4 --confirm
configuring Qt Base, please wait...
Executing in
/usr/ports/lang/phantomjs/work/phantomjs-2.1.1/src/qt/qtbase:
/usr/ports/lang/phantomjs/work/phantomjs-2.1.1/src/qt/qtbase/configure
-static -opensource -confirm-license -prefix
/usr/ports/lang/phantomjs/work/phantomjs-2.1.1/src/qt/qtbase -qt-zlib
-qt-libpng -qt-libjpeg -qt-pcre -nomake examples -nomake tools -nomake
tests -no-qml-debug -no-dbus -no-opengl -no-audio-backend -D
QT_NO_GRAPHICSVIEW -D QT_NO_GRAPHICSEFFECT -D QT_NO_STYLESHEET -D
QT_NO_STYLE_CDE -D QT_NO_STYLE_CLEANLOOKS -D QT_NO_STYLE_MOTIF -D
QT_NO_STYLE_PLASTIQUE -D QT_NO_PRINTPREVIEWDIALOG -qpa phantom -openssl
-openssl-linked -no-openvg -no-eglfs -no-egl -no-glib -no-gtkstyle
-no-cups -no-sm -no-xinerama -no-xkb -no-xcb -no-kms -no-linuxfb
-no-directfb -no-mtdev -no-libudev -no-evdev -no-pulseaudio -no-alsa
-no-feature-PRINTPREVIEWWIDGET -fontconfig -icu -release
g++46: not found

This is the Qt Open Source Edition.

You are licensed to use this software under the terms of
the Lesser GNU General Public License (LGPL) versions 2.1.
You are also licensed to use this software under the terms of
the GNU Lesser General Public License (LGPL) versions 3.

You have already accepted the terms of the Open Source license.


   The specified system/compiler is not supported:

     
/usr/ports/lang/phantomjs/work/phantomjs-2.1.1/src/qt/qtbase/mkspecs/freebsd-g++49

   Please see the README file for a complete list.


ERROR: Failed to build PhantomJS! Configuration of Qt Base failed.
*** Error code 1

Stop.
make: stopped in /usr/ports/lang/phantomjs

This is on FreeBSD 11-stable

uname -a
FreeBSD desk.server.mydomain.nl 11.0-STABLE FreeBSD 11.0-STABLE #37
r312379: Wed Jan 18 14:35:28 CET 2017    
root at desk.server.mydomain.nl:/usr/obj/usr/src/sys/KRNL  amd64

regards
Johan Hendriks