Add i386 build for Mesa

[fathonix]

To start support for muvm and FEX on Ubuntu Asahi, an i386 build of Mesa is necessary to enable 3D acceleration on 32-bit apps such as Wine.

Here's muvm w/ sommelier running Wine64 using FEX + custom FEX RootFS w/ amd64 Ubuntu Asahi Mesa.

[mkurz]

@fathonix Can you share how you achieved this setup? Thanks!

[tobhe]

fwiw we now have a i386 build and some more parts of the stack are WIP. @mkurz see https://kernelpanik.net/vulkan_and_steam_on_ubuntu_asahi/ for instructions on how to set up muvm. We are working on moving all of this to our main ppa.

[mkurz]

How do you generate the rootfs? Is it done via https://github.com/kaazoo/RootFS?
/cc @kaazoo
Thanks!