How to keep biber working

[Jelle Licht]

Guix,

I've noticed some time ago that the biber version that we currently have
is incompatible with the texlive revision we have packaged.

Incidentally, since the latest core-updates merge, biber does not pass
its test suite anymore due to the hardcoded
`perl-unicode-collate'-related hashes. I think we need a more
sustainable (and dynamic) fix for this, as this is not the first time
this has happened.

As far as I know, biber has no dependents other than itself. I could
also downgrade it 2.11 so it works with our texlive packages
again. Should I simply revert the "gnu: biber: Update to 2.12." commit,
or only adjust the [source] and [version] fields of the biber package?

I can push a short-term fix that involves disabling the test suite for
biber nonetheless, as this seems to be required for both version 2.12
and 2.11.

Thoughts?