games/vegastrike/engine clang6 fix

Index: engine/Makefile
===================================================================
RCS file: /cvs/ports/games/vegastrike/engine/Makefile,v
retrieving revision 1.10
diff -u -p -r1.10 Makefile
--- engine/Makefile 26 Dec 2017 19:18:57 -0000 1.10
+++ engine/Makefile 13 Apr 2018 10:02:23 -0000
@@ -41,7 +41,8 @@ CONFIGURE_ARGS += --with-python-version=
--disable-ffmpeg \
--with-data-dir="${TRUEPREFIX}/share/vegastrike"

-CXXFLAGS += -Wno-undefined-var-template -Wno-unused-volatile-lvalue
+CXXFLAGS += -Wno-undefined-var-template -Wno-unused-volatile-lvalue \
+ -std=c++03

CONFIGURE_ENV = \
CPPFLAGS="-I${X11BASE}/include -I${LOCALBASE}/include -I${LOCALBASE}/include/libpng" \
Hi,

here a simple fix turning to C++03 mode.

Regards.