Bump PORTREVISIONS for ports depending on the canonical version of GCC and
lang/gcc which have moved from GCC 4.8.5 to GCC 4.9.4 (at least under some
circumstances such as versions of FreeBSD or platforms).
In particular that is ports with USE_GCC=yes, USE_GCC=any, or one of
gcc-c++11-lib, openmp, nestedfct, c++11-lib as well as c++14-lang,
c++11-lang, c++0x, c11 requested via USES=compiler.