IceCat-78.2 preview on 'wip-icecat-78' branch; need icedove-78.

[Mark H Weaver]

Hi Jonathan, and other fellow Guix!

I've pushed a preview of IceCat-78.2 to the 'wip-icecat-78' branch on
Savannah.  It's ready for early testing by interested parties.  It works
well enough that I've switched to it as my primary browser.  This
version also supports Wayland natively.  However, in case the IceCat 78
preview doesn't (yet) work well for your use case, early testers might
want to make a backup of ~/.mozilla before running it, in case you need
to switch back to 68.  I don't know off-hand whether IceCat 68 would
cope with a profile that 78 has been run on.

There's one thing that needs to be done before this can be pushed to
'master': IceDove needs to be updated to version 78 as well.  For now,
IceDove is almost certainly broken on the 'wip-icecat-78' branch.

Jonathan: you seem to be the defacto maintainer of our IceDove package.
Would you like to work on updating it to 78 on the 'wip-icecat-78'
branch?  We have about 2 weeks before IceCat 78 must be pushed to
'master'.

    Best regards,
        Mark