Testing a patch to align the lang/gcc* ports with other languages and default to lang/gcc5 (instead of lang/gcc as it currently is) we found that games/eduke32 seems to ignore the CXX variable to denote the C++ compiler and simply checks for g++: http://package18.nyi.freebsd.org/data/110amd64-default-PR218330/2017-04-06_19h28m41s/logs/errors/eduke32-20170225_1.log If you want to reproduce this, try the simple patch from PR 218330.
I believe this issue was fixed in https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=217913.
Yes, this appears to be the case, and the commit of that one and the testrun leading to this one just did not work out well timing- wise. *** This bug has been marked as a duplicate of bug 217913 ***