bug#57562: [PATCH] * lisp/emacs-lisp/comp.el (comp-run-async-workers): Fail more gracefully

[Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

>> > I have trouble seeing the actual change amongst unrelated whitespace
>> > changes.  Please show a patch with the minimal necessary change,
>> > without all the reformatting.  Emacs 28.2 is so close to a release
>> > that playing whitespace and formatting games is not appropriate there.
>> Hmm... looks like I sent the patch I had on `master`, sorry.
>> Here is the cleaner `emacs-28` version.
> So this means we will silently skip native-compilation, leaving an
> obscure message in a buffer, is that right?

In *Messages*, I think, yes.

I suspect this message will tend to be repeated later on, whenever
a new `.elc` file is loaded.  In a sense that's good (less chance that
the message will be overlooked) but it also risks hiding other messages.

> Maybe this is the best we can do for emacs-28 so close to the release,
> but for master wouldn't it be better to use delayed-warning instead?

Sounds about right, tho I suspect we might need to do even a bit more on
`master`, like disabling lazy native compilation when we bump into this
problem, to avoid repeating that same error message, or trying harder to
find a writable directory.


        Stefan