When I invoke `guix pull` when `GUIX_BUILD_OPTIONS` contains a call for `--with-graft`, `guix pull` fails due to `with-graft` not being a valid option for `guix pull`:
Command-line transcript: guix pull guix pull: error: [email protected]: unrecognized option Having `guix pull` ignore `GUIX_BUILD_OPTIONS` may be a hack fix, but it could break other people's workflows since `guix pull` has some options for building (i.e: `--cores` and `--no-grafts`). Suggestions: Adding `with-graft` support to guix pull (if that's even applicable). Having guix-pull just ignore the option and return a warning. Split up GUIX_BUILD_OPTIONS into a per-command set of flags (i.e: GUIX_BUILD_OPTIONS_PULL).
