* guix/scripts/package.scm (<manifest-entry>): Add 'inputs' field.
(manifest=?, lower-input): New procedure.
(profile-derivation)[builder]: Add #:log-port argument to
'union-build'.
[ensure-valid-input]: Remove.
Add each entry's inputs to the input list.
(options->installable): Return just the list of entries.
[package->manifest-entry]: Set 'inputs' field.
[canonicalize-deps]: Rename to...
[deduplicate]: ... this. Remove input fiddling.
(guix-package)[process-actions]: Use 'manifest=?' to compare the new
and old manifests. Pass directly PROF-DRV to 'show-what-to-build'.
Pass #:print-build-trace #f to 'set-build-options'.