[bug#51972] [PATCH core-updates-frozen] gnu: elogind: Revert changes to polkit build time detection.

[Josselin Poiret via Guix-patches via <guix-patches@gnu.org>]

Ludovic Courtès <ludo@gnu.org> writes:

> Could you explain what user-visible bug that fixes?
>
> I suppose commit abc9a9b74549016bc749392d3cecf86386286145 by Timothy
> this morning did not put an end to our polkit problems, right?

Right!

elogind doesn't depend on polkit when building it, but uses it when
running to check permissions of users to interact with the login daemon:
shutting down, rebooting, or changing VTs.  However, elogind checks for
the VT changing permission (org.freedesktop.login1.chvt) when trying to
activate a session.  An upstream commit that found its way into his
release broke the runtime detection of polkit, and so it was impossible
for elogind to check for the needed permissions.  This meant that among
other things, wlroots-based compositors could not take control of a seat
and so would not start.

I think we're not entirely through for polkit/elogind and friends
though, as GDM isn't able to initiate shutdowns curretly if I'm not
mistaken, but that might just need some polkit rules tweaking.  I'll
look into it when I finish rebuilding elogind dependents locally (I was
using grafts to test this patch).  At least I'm able to run sway now!

Best,
Josselin Poiret