Hi Ludo,

as discussed before I have looked into the problems of timestamps in the
zip files.
I looked at the way this is solved in ant-build-system with jar files
and thought that this could be done in a more elegant way.
Because of this I wrote a simple frontend for LibArchive in C that
repacks archives and sets their timestamps to zero and disables
compression as it is done in the ant-build-system.
Creative as I am the program is called repack.
You find a git repository attached with the history of the repack program.
The attached patches add repack to Guix and use it for pwsafe and the
ant-build-system.

This is a work in progress version: If you like these changes I will
work on missing details so that we can add it, otherwise now would be a
good point to stop development on these changes.
I can still fall back to the variant that ant-build-system uses now for
pwsafe.

It would be nice if you could find the time to review everything and
tell me what you think about the patches.
The changes trigger a lot of rebuilds so it will take some time to build
dependencies of the required programs.

The repack tar contains a bare git repository with the program.
Because I could not yet find a place to host the repository you need to
unpack it somewhere, create an archive with the source code and change
the guix definition of repack to use that source.

Tim.