Many test failures, most of which seem to be permission errors (maybe
related to the =guix shell -CPWN= container?), but the
=crates= and =packages= test failures are more mysterious.

Output of guix describe:

guix ed95dde
  repository URL: https://git.savannah.gnu.org/git/guix.git
  branch: master
  commit: ed95ddeb1e58c314f2e22b4cd35986042f3e2f21
nonguix e6b3bb8
  repository URL: https://gitlab.com/nonguix/nonguix
  branch: master
  commit: e6b3bb87a46024cd6b2fb1a1cad1387de0053f44