And likewise, prevent building with mingw-gcc for Windows if it's GCC 6/7. The check for the Server platform was unnecessary as its `release` template doesn't use `-O3`/`-Ofast`.
And likewise, prevent building with mingw-gcc for Windows if it's GCC 6/7. The check for the Server platform was unnecessary as its `release` template doesn't use `-O3`/`-Ofast`.