Hi Daniela, Have you tried './pre-inst-env guix build ...' instead of 'guix build ...'?
The difference is that the former command will look for package definitions in your checked out, and modified, version of Guix. The latter command looks for package definitions in your installed version of Guix. Your modifications will be seen by this command after you submit a patch, it is committed, then you update your installed version with a 'guix pull'. Best regards, Paul.
