Re: master 37889523278: Add new `swap` macro and use it

[Stefan Kangas <stefankangas@gmail.com>]

Gregory Heytings <gregory@heytings.org> writes:

> - this is about GCC < 4.8 (ten year old compilers)
>
> - on a specific platform (PowerPC, which is rarely used nowadays)
>
> - on which GCC displays a bogus "value computed is not used" warning (a
> warning, not an error!)
>
> - when __typeof__ is used in a cast operation on the return type of a
> function.
>
> That's a far cry, to say the least, from "__typeof__ is unusable under
> compilers older than GCC 4.8".

This is my conclusion as well.  I've spent several hours trying to track
down the actual fix in GCC to get more information about the severity of
the warning, but had to give up because the time I had available ran out.

The reason why GLib introduced their change, AFAICT, was that people
wanted to compile some program depending on it with -Werror.

Based on what I found so far, which honestly wasn't much, I think it's
just a bogus warning, and nothing to worry about.  If anyone can provide
more information about this that would point to something more critical,
please do tell.

It also remains to be seen if we will even get that warning in Emacs,
since it might only show up under specific conditions.