[bug#50170] [PATCH core-updates-frozen] gnu: mesa: Update to 21.2.1.

[John Kehayias]

Hi everyone,

I know we're working on getting core-updates-frozen in shape to merge, but with 
a few more Mesa updates out recently I thought maybe I can sneak this in as an 
addendum to the current Mesa patches. I checked it builds on x86-64 and 
modified the patch which removes the troublesome (i686) test to still apply 
here. No other changes to the build process I could see. 21.2.0 was out earlier 
but was a development release; this is the first regular release for 21.2.

If I may, I would suggest seeing if this builds on the CI for other 
architectures without major changes, and if so would recommend this update. 
Mesa has been moving quickly with bug fixes and enhancing their graphics 
drivers, so with the extended time between core-update merges would be great to 
be up to date for this current merge.

And if not, this can be the start of the next core-updates Mesa update (maybe 
Mesa can be moved to a quicker updating process?). There is also a further bug 
fix release for 21.1, so we could bump to 21.1.7 from our current 21.1.6 in 
core-updates-frozen.

Let me know what you think and anything else we need on this front.

John