The `mesa` formula currently uses a mesa.freedesktop.org/archive/
`stable` URL but it redirects to archive.mesa3d.org. Upstream links
to archive.mesa3d.org as the location to find Mesa releases, so we
should update the formula URLs accordingly.
This updates the `Xorg` strategy to be able to handle
archive.mesa3d.org URLs, so livecheck will continue to be able to
check `mesa` without needing a one-off `livecheck` block. [This would
also work for `mesalib-glw` (which has an archive.mesa3d.org `stable`
URL) but that formula is deprecated.]
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