* guix/packages.scm (<package>)[inputs]: Mark as thunked.
(package-derivation)[expand-input]: Remove case where the input is a
procedure.
* tests/packages.scm ("trivial with system-dependent input"): Remove
`lambda', and use (%current-system).
* gnu/packages/bootstrap.scm (package-from-tarball): Likewise for `inputs'.
(%bootstrap-glibc, %bootstrap-gcc): Likewise.
* gnu/packages/scheme.scm (mit-scheme): Likewise.
Ludovic Courtès