bug#20765: (no subject)

[Leo Famulari]

Another reason to not compress Python eggs is that the contents of the
zip archives introduce non-determinism through their timestamps.

You can see it in action:
$ git checkout fe17fb4a2c897fd9186f91887f5af63dd00d227a
$ ./pre-inst-env guix build --rounds=2 acme

If you save the output between rounds, you can use diffoscope to confirm
that the differences between the rounds are the timestamps of the
contents of the eggs.