[Mesa-maintainers] Building Mesa GIT with LLVM prior to 3.9

[Emil Velikov]

Hi all,

As you may know, different components in Mesa use LLVM for various purposes.

In particular:
 - 3.3.0 for the aux gallium module, gallivm
 - 3.6.0 for the opencl state-tracker, clover
 - 3.9.0 for multiple drivers r600, radeonsi, radv and swr

AFAICT gallivm is build on Windows, and using newer LLVM in there is
rather hard/messy.

On the other hand, Clover is built on Linux/BSD platforms. Which seems
to be OK wrt availability and the respective packaging.
So leaving the former out for now, I'm wondering if we cannot bump the
Clover requirement to 3.9.0.

Quick search shows:
 - Debian - 3.9 since stretch (stable)
 - Ubuntu - 3.9 since trusty (14.04LTS)
 - FreeBSD - 3.9
 - openSUSE - 3.9 since Leap 42.2 (unofficial), official since Tumbleweed
 - Fedora - 3.9 since F25
 - Gentoo - 3.9 is marked as stable
 - Archlinux - using 5.0

Note: older enterprise distributions seems to be in the cold.
Yet there's little point in them building Clover since it cannot be
run on those.

Thanks
Emil