Arch legacy grub compatibility

[jelly]

This is the final piece for generating a successful booting Arch Linux VM. Arch Linux can't use the normal grub stage as the the open bootloader specification patches are not merged upstream yet.

[gicmo]

@jelly I wonder if we need bootpath. We have logic to determine the grub home (the path that contains the grub2 directory): in the org.osbuild.grub2 stage it is via the rootfs and bootfs options, i.e. if they are specified and different then grub is on a separate boot partition and thus the prefix is /, otherwise it is /boot. I think the same logic could be applied for the org.osbuild.grub2.legacy stage. and thus you could just use GrubConfig.grub_home instead of the new bootpath config option. The variable for the template is called root in the grub2 stage:

osbuild/stages/org.osbuild.grub2

Line 272 in a9e1070

search --no-floppy --set prefix --file ${root}grub2/grub.cfg

[jelly]

That sounds like a much better solution!

[gicmo]

LGTM