unreproducible zlib/deflate compression in ZIP/APK files

[Bernhard M. Wiedemann]

If I read it correctly, there are different zlib implementations that 
will turn identical uncompressed data into different compressed versions.
As long as the uncompressed data matches, that is fine security-wise.

This relates to #12 of our
  https://reproducible-builds.org/docs/commandments/

> 12. If Thou publishst binaries, Thou shall take note of your build inputs

If you knew exactly, which zlib version was used, it should be possible 
to reproduce compressed results.

Ciao
Bernhard M.