Migrating packages to Guile 3.0

[Ludovic Courtès]

Hello Guix!

I’ve pushed a ‘wip-guile3.0-packages’ branch, which renames “guile-next”
to “guile”, renames “guile3.0-” packages to just “guile-”, and changes a
few more occurrences of ‘guile-2.2’ to ‘guile-3.0’ in package inputs.
It should start building here:

  https://ci.guix.gnu.org/jobset/wip-guile3.0-packages

We’re talking about the subset of packages known to support Guile 3.0,
which includes all the dependencies (and dependents, hopefully) of Guix,
plus a bunch of other packages.

Initially I thought about applying the patch to ‘master’.  However, it’s
not that simple: we’d also need to have all the modules for Shepherd
compiled for Guile 3.0, same for mcron, and same everywhere we use
‘with-extensions’ (for ‘guix pack’, (gnu system vm), etc.).

Thus, I’m inclined to do the big switch in ‘core-updates’, where we
could directly change ‘default-guile’, and thus everything would switch
to Guile 3.0 at once.  (In the meantime, the branch above allows us to
test the packaging bits.)

Thoughts?

Thing is, it’d be great to have Guile 3.0.1, which could happen anytime
now but just needs synchronization.

Ludo’.