bug#51094: Check if run-with{-idle, }-timer needs to create a timer

[Eli Zaretskii]

> From: Philip Kaludercic <philipk@posteo.net>
> Date: Fri, 08 Oct 2021 09:36:22 +0000
> 
> I have seen a few packages use run-with-timer or run-with-idle-timer,
> where the SECS parameter is configurable with a user option. When this
> timer doesn't repeat itself and it makes sense to set SECS to 0 when you
> want something to run immediately, I don't think it makes sense to
> create a timer object.
> 
> The following patch would remove this overhead, and calls the function
> immediately if it makes sense.

I'm not sure we should care, but in any case, what you do there
requires a comment explaining the rationale.

Thanks.