Similar story for s390x virtio qemu bootloader support code. Currently
sources are in src:qemu, should be arch:all, can be compiled with
native or s390x cross compiler.
So far we have infrastructure to declare a particular source package
to be build on particular arch, but then one needs to split that arch
bootloader code into separate package... It would be nice to declare
Arch:all packages that are Build-Arch: s390x. That way e.g. there are
multiple arch:all builds despatched to build most arch:all packages on
arch:all builder, this arch:all package on s390x, and all the arch:any
packages everywhere else.