hydra-eval-guile-jobs: Allow use of the installed Guix.

Dependencies

• [2] QMW24O5S Add support for Guile & Guix.
• [3] Y6H7Y3OT Capture the path to `guile', when available.

Change contents

• replacement in src/script/hydra-eval-guile-jobs.in at line 5
  [2.2850]→[2.2850:3081](∅→∅)
  − # Make sure no undeclared dependency is leaked. Guix has to be

  − # provided as an input through Hydra. Guix itself must thus be built via a

  − # recipe written in the Nix language.

  − unset GUILE_LOAD_PATH

  − unset GUILE_LOAD_COMPILED_PATH
  [2.2850]

  [2.3081]
  + # Keep the host's GUILE_LOAD_PATH unchanged to allow the installed Guix to

  + # be used. This moves Guix modules possibly out of control, but solves

  + # bootstrapping issues.