Fix sdk install phase

[urob]

zephyr-sdk doesn't contain hosttools-standalone scripts for non-linux platforms, resulting in a build failure on Darwin without the force flag.

[urob]

There is one other issue on Darwin builds, which I am not sure how to best resolve: qemu_full requires ceph, which is only available for linux platforms. I am not sure how important ceph is, maybe the dependency can be overridden to be dropped?

[adisbladis]

qemu_full requires ceph, which is only available for linux platforms. I am not sure how important ceph is, maybe the dependency can be overridden to be dropped?

Could we use qemu instead of qemu_full on darwin?

[urob]

Could we use qemu instead of qemu_full on darwin?

This should fix the dependency, but I am not sure how it restricts functionality. But perhaps the best course of action in lieu of alternatives?

[adisbladis]

We could of course simply override and disable ceph support, but that would mean building qemu from source.

Actually the best fix would be to fix qemu_full in nixpkgs.
A quick fix would be to disable cephSupport on darwin.

If you make a PR cc me please :)