Fixes <http://bugs.gnu.org/15194>.
Reported by Mark H Weaver <mhw@netris.org>.
* gnu/packages/patches/hop-bigloo-4.0b.patch: New file.
* gnu-system.am (dist_patch_DATA): Add it.
* gnu/packages/scheme.scm (hop): Use it.
* gnu/packages/scheme.scm (bigloo): Update to 4.0b. Patch the
`configure-gc' scripts. Remove `patch-absolute-file-names' phase.
* gnu/packages/patches/bigloo-gc-shebangs.patch: Adjust to new version.
* 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.