Sync with upstream

[emersion]

So far I've been doing this:

env GIT_DIR=$PWD/../systemd/.git git format-patch --stdout -1 <hash> | git am

And then manually add a ref to the original commit. There may be a better way to do this.

[kennylevinsen]

What commit did you sink up to?

[emersion]

I've started from https://github.com/systemd/systemd/commit/c4e48030cf299b56668b1cd360c4ec93e7f97b20, and just processed these three commits to see how the process could look like.