Before this, something like "guix package -i glibc" could fail because
glibc lists linux-libre-headers as a propagated input (which would be
added as a dependency in the manifest) but the linux-libre-headers
output could be unavailable, leading to an error like this:
path `/nix/store/4v2bk8sx5cm166gks3fi3q7d9zchibnk-linux-libre-headers-3.3.8' is not valid
This patch adds such dependencies as inputs of the profile derivation.
* guix/scripts/package.scm (profile-derivation): Accept package objects
in the `deps' field of an element of PACKAGES. Convert them to their
output path for BUILDER, and add them to the inputs of the
`build-expression->derivation' call.
(input->name+path): When INPUT doesn't contain a package object,
return it as is.
(guix-package)[process-actions](canonicalize-deps): Expect DEPS to
contain package objects, and leave them as is.