Test ALPHA ISOs to allow Gentoo to be able to rebuild them weekly
This is testing both new bootloader creation and the switch to sys-kernel/gentoo-kernel for easier maintenance for releng.
See the larger project page for more info: https://wiki.gentoo.org/wiki/User:Immolo/RelEng
Catalyst was never designed to build live media for a different arch to one it was building. Likely as back in the day it was faster to compile natively than use the slow emulation on a 1/2 core x86_64 CPU.
So in short the ISO creation assumes it's running on the same arch as the target.
This is really easy to workaround on platforms with GRUB support, but I am not this lucky with arches like ALPHA. (Please port GRUB to everywhere.)
Ideally we don't want to rewrite the build process so it builds inside the target chroot. It adds too much complexity and be much harder to troubleshoot IMO.
So this solution hopefully emulates the native building steps in a way that can used in a cross build solution.
QEMU does not support ALPHA bootloaders so I'm completely shooting in the dark with this. In a effort to be fully transparent, an LLM was used to breakdown the boot process and how the commands run natively. Bootloaders are black magic at the best of times so there was no chance of me figuring this out from random blogs and forum posts like I prefer.
There is however zero LLM code used, but my code assumes it taught me correctly. So while your house isn't going to burn down, I have little faith it works.