Branch (and team?) for mesa updates

[John Kehayias]

Hi everyone,

With our move to a branching strategy for patches that require many rebuilds, I 
would like to propose a branch for Mesa updates. Based on how Mesa has been 
developed the last few years, there should be frequent (roughly a couple of 
months or quicker) releases that shouldn't be breaking anything or requiring 
lots of packaging work.

Famous last words, I know, but at least in the last few years the only big 
change I know of was the one we hit on the last core-updates cycle with old 
hardware being dropped. The previous cycle had some build changes, perhaps due 
to missing many intermediate version changes. Both were rather self-contained 
and resolved quickly.

So, I have submitted a patch for the latest stable release at 
<https://issues.guix.gnu.org/64175> I'm aware of one other patch that should 
also go here, <https://issues.guix.gnu.org/64044> are there any others?

I've tentatively labeled with "mesa-updates" as a proposed branch name. With 
Mesa's release cycle I propose keeping this as a branch for Mesa updates, and I 
suppose related required changes (say libdrm). If everything goes smoothly, we 
can give the build farm some time to build everything, check for any breakages, 
and then push to master with substitutes available. Master can be merged into 
this branch just prior to a patches going to this branch with the expectation 
merging back to master will be soon after and changes are only affecting 
packages that won't be touched on master anyway. I think this should be 
relatively clean and straightforward, a good use of our new branching/building 
strategy.

Thoughts? Can someone set up a build job for this branch and/or let me know how 
to do that? (I would also require access to Cuirass.)

Do we want a "Mesa team" or something a bit larger? Not sure what exactly, 
since "graphics" is perhaps too broad. Happy to help spearhead the Mesa front 
for Guix (the very package that got me first involved in the patching process).

Thanks!
John