Previously non-matching tags were not filtered out from the list of
valid versions. It wasn't an issue though cause all current releases do
match the pattern we were looking for. But that will not be the case for
much longer when stable releases are added into the mix.
Right now all *.eln files produced by native compilation links against a
GCC shared library with a absolute file path, rather than to the version
of the shared library included in the app bundle.
This means for now we need to ensure the homebrew gcc formula is
installed for native-compilation to work.
More details are available here:
https://github.com/jimeh/build-emacs-for-macos/issues/53
