Disable the _static_tuple_c extension module to workaround Python 3.8 problems
    
    On Python 3.8, _static_tuple_c is broken, so we temporarily switch to the
    pure Python fallback.
    
    In order to not break things, all other extension modules that cimport from
    _static_tuple_c were disabled and switched to their pure Python versions as well.
    
    Other disabled modules:
     - _chk_map_pyx
     - _dirstate_helpers_pyx
     - _bencode_pyx
     - _btree_serializer_pyx
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1760260
    https://bugs.launchpad.net/bugs/1844684