Ready for Guile 2.2!

[Ludovic Courtès]

Hello Guix!

Exciting times!

As of commit 608e42e7c92114497e7908980424288079acee1e, Guix builds with
Guile 2.2 (to be released sometime within the next 24 hours) and the
whole test suite passes.

All the dependencies of Guix except Guile-SSH (optional; use for
offloading and for ‘guix copy’) are already compatible with Guile 2.2.

Guile 2.2 comes with a new compiler and a new virtual machine.  As a
result, one of the main user-visible changes is that things are faster.

Building Guix with 2.2 is the first migration step.  The next steps are:

  1. Renaming ‘guile-next’ to ‘guile’ and making 2.2 the default.  Some
     packages (notably Guile-SSH, GDB, LilyPond) don’t work with 2.2 yet
     so for these we’ll change ‘guile’ to ‘guile-2.0’.  This can start
     as soon as this week.  :-)

     We’ll replace ‘package-for-guile-2.2’ with ‘package-for-guile-2.0’,
     though I don’t think it’ll make sense to keep both a 2.0 and a 2.2
     version of all the packages.

  2. Use 2.2 to build derivation, as the default #:guile-for-build
     (aka. ‘default-guile’.)  This can be done on the next
     ‘core-updates’ cycle and if everything goes well, it will be
     completely transparent.

Happy hacking!

Ludo’.