x86_64 is used as a baseline: the "x86_64" entry, whatever status it has,
is transformed into "all", and then the other entries in ARCHITECTURES
either dropped or rearranged appropriately.
The 2nd patch in patch-2.7.6-gcc2.patchset is almost identical to
the 2nd one in tar-1.30-gcc2.patchset, and the files they patch:
* tar-1.30/gnu/backupfile.c * tar-1.30/gnu/parse-datetime.y
* patch-2.7.6/lib/backupfile.c * patch-2.7.6/lib/parse-datetime.y
are identical before and after the patch. There is only one diff,
in line 3: we have a "2017" for tar and a "2018" for patch.
