nixos/etc-overlay: make the etc overlay compatible with nixos-enter and nixos-install

When using nixos-enter (and so also nixos-install) on a system with etc-overlay enabled,
he activation script gets called directly, and there is no systemd running.
This violates a couple of assumptions in the etc-overlay activation script which
assumed that it only ever ran when switching into a new generation and that
the very first /etc would always have been set up by the systemd initrd.

As more and more things are being moved into systemd components (initrd services,
mount units, tmpfiles, etc), I think that it is going to become increasingly
difficult to stay compatible with these tools, but at least for now there is
no real alternative and so we probably want to be able to install systems
with etc-overlay enabled.

0 files changed, 0 insertions, 0 deletions