> how can I use (guix hash) on the build side? It requires the libgcrypt shared > library and that's not available on the build side...
Depends. For a one off package I'd add it to native-inputs. Otherwise you can create a new build-system that wraps the gnu-build-system and extend the gnu-build-system's implicit inputs with libgcrypt. Which is basically just automatically adding it to native-inputs for you.
