bug#32169: 27.0.50; Wishlist: cleanup of thread-last-error

[Eli Zaretskii]

> From: Michael Albinus <michael.albinus@gmx.de>
> Date: Mon, 16 Jul 2018 09:18:48 +0200
> 
> 
> When a thread has died, `thread-last-error' reports the reason. But
> there is no possibility to cleanup this last error, which makes it
> inconvenient to check for errors in further threads. A function
> `cleanup-thread-last-error' or alike would be helpful.

How about having thread-last-error clear the error as a side effect,
perhaps when called with an optional argument?

(Btw, I'd rather we made error reporting in non-main threads much more
solid than what we have now.)