clang vs gcc warning flags

[Ryan Libby]

On Wed, Jan 6, 2021 at 12:06 PM Konstantin Belousov <kostikbel at gmail.com> wrote:
>
> On Wed, Jan 06, 2021 at 11:53:13AM -0800, Ryan Libby wrote:
> >  - Wnested-externs I just do not understand.  We have specified this
> >    warning flag for some 25 years but to me it seems completely without
> >    value.  I suggest we just delete it.
> I suspect this warning is to flag style(9) violations.

Which aspect do you mean?  I don't see it mentioned explicitly, but I
know some of style(9) is reading between the lines.

If it's that objects with external linkage should be declared in
headers, I think that doesn't address most of the cases where extern is
actually used in our .c files.

Maybe the answer should be different for contrib software (where we
don't generally enforce style)?