This didn't work reliably because it raced with the remounting of /.
So if you were unlucky, then / was read-only by the time we ran
"alsactl store". Now the sound card state is saved before anything is
unmounted/remounted.
The services systemd-random-seed-save.service and
systemd-update-utmp-shutdown.service from systemd 203 don't work,
because they have a RequiresMountFor dependency on /var/lib and
/var/log. Such a dependency produces a cycle, causing systemd to drop
those services:
Fixing conflicting jobs by deleting job poweroff.target/stop
Deleting job systemd-poweroff.service/stop as dependency of job poweroff.target/stop
Deleting job umount.target/stop as dependency of job systemd-poweroff.service/stop
Deleting job -.mount/start as dependency of job umount.target/stop
Deleting job systemd-random-seed-save.service/start as dependency of job -.mount/start
Deleting job systemd-update-utmp-shutdown.service/start as dependency of job -.mount/start
Dropping the RequiresMountFor doesn't work either, because then
/var/... may have meen unmounted or remounted read-only.
Upstream systemd fixes this by doing the actual work from an ExecStop
action in an already-running service than conflicts with
shutdown.target. So I backported that here. The main consequence is
that wtmp shutdown records now get written properly.
The main lesson: shutdown.target is useless for pulling in services
during shutdown if they need to write anywhere.
The change was supposed to trigger a re-build to fix a broken GHC binary
on the Hydra build farm, but now it turns out that the cause for the
errors we're seeing isn't GHC: all kinds of (non-Haskell) packages are
broken.
I tried jailbreaking, but this didn't work as llvm-general is an
optional (but enabled by default) dependency.
Manual patching revealed idris gets confused over the
llvm-general/llvm-general-pure split.
