[PATCH] Update Julia (and use smaller tarball)

[Ricardo Wurmus]

Hi Guix,

the attached patches update julia to the latest version.  The second of the
two patches makes a couple of changes to allow us to use the much smaller
release tarball.  This made it necessary to add a few tarballs to the inputs
manually.

I think this is nicer now, because we no longer download an unnecessarily
large bundle, and we see much clearer now what we still need to work on in
future updates.

~~ Ricardo