Bundle Racc into StdLib.
    
    It is increasingly hard to maintain default gems extracted from StdLib
    into gems. If they are overlapped by independent versions, it is even
    harder, because the overlapped versions would need to provide symlinks
    back to StdLib \[[1]\]. On top of that, the layout differs from
    upstream, where default gems are always available.
    
    Because these small nuances can make hard discoverable race conditions
    during Ruby application loading and runtime, it will be best to keep the
    default gems bundled.
    
    [1]: https://src.fedoraproject.org/rpms/rubygem-racc/pull-request/1