Before that, any profile generation built when '-p' is used would
effectively become a permanent GC root because the symlink in
/var/guix/gcroots/auto would point directly to /gnu/store/...-profile.
* guix/scripts/package.scm (maybe-register-gc-root): Rename to...
(register-gc-root): ... this. Remove conditional, and replace call to
'canonicalize-path' with (string-append (getcwd) "/" ...).
(guix-package): Call 'register-gc-root' only if PROFILE is different
from %CURRENT-PROFILE.
* tests/guix-package.sh: Add test case.