bug#66381: 29.1; Auto-revert not polling files when notifications are enabled

[Eli Zaretskii]

> From: Michael Albinus <michael.albinus@gmx.de>
> Cc: Eli Zaretskii <eliz@gnu.org>,  66381@debbugs.gnu.org
> Date: Tue, 10 Oct 2023 20:03:48 +0200
> 
> I've checked the other file notification backends, and it turns out,
> that none of them reports unmount events. So I have extended the patch,
> the unmount event is propagated now in all backends (under different
> event names), and it causes to stop the respective file notification
> watch.
> 
> This works for all but the w32notify backend. I dont know whether this
> library supports a kind of unmount events, and even in case it does, I
> wouldn't be able to implement this. Eli, do we want to do something
> here?

I don't know, I will have to test this.

Could you please help me by showing some Lisp I could use to see if
unmounting a volume gets reported in some way to the
file-notifications machinery?  I have very little free time these
days, for more than one good reason, but would like not to postpone
investigating this for too long, which will happen if I need to find
the recipe myself.  TIA.