bug#25987: 25.2; support gcc fixit notes

[Andrea Corallo]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Andrea Corallo <akrl@sdf.org>
>> Cc: David Malcolm <dmalcolm@redhat.com>,  25987@debbugs.gnu.org
>> Date: Thu, 15 Oct 2020 14:23:05 +0000
>> 
>> > I'm not sure how a separate file comes into this.  Aren't we talking
>> > about the "normal" GCC diagnostic output, just augmented by hints?
>> > That has the advantage that it is also human-readable, and could help
>> > the user make changes other than accepting the hints.
>> 
>> I explained this in my last mail on this thread, to make it short using
>> stderr can't work reliably for parallel builds.
>
> That's not a problem the feature discussed here can fix: it happens
> with any parallel build run by "M-x compile".

Yes, but this is less severe as the line is tipically preserved and the
regexps we use for the goto-error are not affected, so in practice it
works.  The case of the patch is more sensitive.

> The solution to that is
> elsewhere (e.g., in using the GNU Make's command-line switches which
> control parallelsim).

That is saying is good enough.  I'm fine with that in case, but this was
to explain why the separate file came in.

  Andrea