Yeah it looks like arch is 'supported', but it doesn't really work. See here, here and here.
So all that remains is to add arch to the CI, and... well I don't know if anything but bugging the arch people can realistically work here.
BTW, referring back to my original post above, the friend I talked about uses Arch, and since aspcud failed, he used the internal solver, often getting stack overflows in the process. I skipped over these details when describing his woes.