llvmpipe broken on arm64 (10.0_RC2)

[adr <adr%sdf.org@localhost>]

The only way to launch applications using opengl (a PI4 here) is
to force mesa to use softpipe with the environment variable:

GALLIUM_DRIVER=softpipe

Note that sdl could try to use opengl even if the video driver is
set to x11. One could use:

SDL_RENDER_DRIVER=software SDL_FRAMEBUFFER_ACCELERATION=0

But that could bring other issues, for example:

https://bugs.scummvm.org/ticket/14530

Yes, I discovered this trying to play this Christmas Monkey Island 2.

Anyone knows the state of this in current? It seems there is more
interest on arm64 nowdays around here.

adr.