(cherry picked from commit fcde178)

(cherry picked from commit 0fa04d6)

It is unfortunate to cherry-pick something with release notes to the
release staging branch so close to the release. But the change is to a
new service so no one comming from 18.03 would be surprised to a
last-minute change in behavior. Furthermore, the change is a month old
and it appears it only wasn't cherry-picked already by mistake.

2a6e4ae and
e51f736 reverted a bit too much, and I
initially missed this when reviewing. The release notes already still
mention this change, too.

(cherry picked from commit 359d00f)

For technical reasons, we cannot easily add a warning to top-level
definitions, so 2a6e4ae and
e51f736 reverted the deprecation. But
we can still remove mention of the would-be deprecated definitions to
steer people towards using the preferred alternatives.

(cherry picked from commit e39a73c)

This fixes nspawn containers with older systemd inside currently failing
to start.

See:
NixOS/systemd#23
systemd/systemd#10104
NixOS/nixpkgs#47253
(cherry picked from commit c3cc34f)

numpy, scipy: Fix some nativeBuildInputs  for 18.09

…18.09

(cherry picked from commit a054f26)
Backport of #47491

(cherry picked from commit d9f7d27)