Hardcode the compiler version in the build key once and for all
    
    * Sat Jan 05 2019 Kevin Kofler <Kevin@tigcc.ticalc.org> - 3.3.8b-77
    - Hardcode the compiler version in the build key once and for all
    
    It does not make sense to have to mess with the build key again and
    again at each GCC major version, nor does the current situation where
    even a point release of GCC will change the build key (because the build
    key patch has not been updated since GCC 6) make any sense whatsoever.
    GCC major versions no longer carry any ABI meaning as in the days of GCC
    2.95 vs. 3.0. And nobody really uses a GCC older than 4.* anymore. So we
    just hardcode the compiler version in the build key to "4.*".