* hydra.scm (hydra-jobs): Return one job for each non-bootstrap package.
* hydra.scm: Redirect the output port to the error port. (package-job): Return a name/thunk pair. (hydra-jobs)[system]: Use either the `system' key (a symbol) in ARGUMENTS, or (%current-system)'.
* hydra.scm: New file. * Makefile.am (EXTRA_DIST): Add it.