* .dir-locals.el (scheme-mode)[gexp->derivation]: Define indentation rule.
* guix/scripts/pack.scm (debian-archive): New procedure.
(%formats): Register the new deb format.
(show-formats): Add it to the usage string.
* tests/pack.scm (%ar-bootstrap): New variable.
(deb archive with symlinks): New test.
* doc/guix.texi (Invoking guix pack): Document it.
* NEWS: Add news entry.
