Hello Nigko and Attila.  My current belief is that any `local-file'
referring to outside the .guix-channel directory cannot work in channels
in all situations.  (Attila’s hashes files are inside guix-crypto’s
.guix-channel src directory.  They are fine.)

At first glance, Guix is faulty and does not respect all symlinks
in `absolute-dirname'.  The following diff should be applied to
guix.git, to resolve symlinks before computing dirname, not after: