bug#40839: Shepherd activation .GO files are not cross-compiled ... and the Hurd

[Mathieu Othacehe <m.othacehe@gmail.com>]

Hello!

>> This is because running grub-install needs root permissions, to mess with
>> /dev/something in order to write the MBR I guess.
>
> Hmm...so we need to do some work, is that bad?

Not sure yet, but I'll investigate it.

>> We could also create a Hurd ISO if grub-mkrescue (that is used to make
>> the ISO bootable), supports the Hurd.
>>
>> Adding Ludo that might have some insight here.
>
> Hopefully -- this is also pretty out of my comfort zone, otoh I am
> very motivated to get this going. :-)
>
> I have been wondering about the branch name in combination with its
> functionality: can/will/could "wip-disk-image" also be used for
> guix system init/reconfigure (we don't have qemu on the Hurd)?

Note that "init" and "reconfigure" options do not use Qemu. "init" will
roughly populate a store directory and install a
bootloader. "reconfigure" will re-install the bootloader with new system
derivation.

While it certainly won't work out of the box for the Hurd, it may be
less tricky than the image support.

I sent a first version of the wip-disk-image to review and rebased it on
master. Now, I'll focus on improving Grub support on this branch (for
MBR based booting), hoping it will help us to get Hurd support later on.

Thanks,

Mathieu