I used it to run `make localmodconfig` in a linux build, others might find it useful as well. Should I contribute it to the cookbook or Guix itself as well?
``` (define (error-before phase pkg) (package (inherit pkg) (arguments (substitute-keyword-arguments (package-arguments pkg) ((#:phases phases) `(modify-phases ,phases (add-before (quote ,phase) 'error-on-purpose (lambda _ (error "error on purpose"))))))))) ```