bug#35510: My GNOME sound settings occasionally get lost

[Mark H Weaver <mhw@netris.org>]

On my x86_64-linux Guix system, I run GNOME 3 within Wayland.  However,
I need to keep 'slim-service' around for one purpose only: to
occasionally remind GNOME sound settings of my preferred "alert" sound,
since it forgets several times per month.

I personally find the default "Drip" sound to be intolerable.  However,
no matter how many times I tell GNOME to use "Sonar" instead, it seems
to only remember that setting for a week or so, and then reverts back to
"Drip", much to my annoyance :-/.

To make matters worse, the GNOME sound settings doesn't work within
Wayland.  It launches, and I can view my settings, but if I change *any*
sound setting, it immediately crashes.  When this happens, I shut down
my Wayland session, relaunch SLiM, log into GNOME within Xorg, reset the
alert sound to "Sonar", and then switch back into Wayland.

In the meantime, if anyone knows the magic incantation to change the
GNOME alert sound to "Sonar" without using GNOME sound settings (and
preferably from the command line) I would be grateful.

Note that I'm running recent 'master', but pre-staging-merge.  It's
possible that the problem was fixed in 'staging'.  I'll report back
after I finish building my post-staging-merge system.

       Mark