Re: master b99ec5d 3/3: Work around __has_attribute bug in clang 3.4

[Philipp Stephani]

Am Sa., 23. Jan. 2021 um 20:42 Uhr schrieb Paul Eggert <eggert@cs.ucla.edu>:
>
> On 1/23/21 2:11 AM, Mattias Engdegård wrote:
> > 23 jan. 2021 kl. 01.46 skrev Paul Eggert <eggert@cs.ucla.edu>:
> >
> >> Perhaps someone who can build on macOS directly can provide more info 
> >> about the problem. I had no problem building with clang 11.0 on Ubuntu but 
> >> Apple's clang is special.
> >
> > Apple's clang seems to come with a builtin
> >
> > #define __nonnull _Nonnull
> >
> > which clashes with the the one in lib/cdefs.h. Perhaps we should call it 
> > something else.
>
> Thanks for the diagnosis. Although calling it something else would
> obviously work, it would require renaming __nonnull everywhere within
> Gnulib (and eventually Glibc), and that would be entirely contrary to
> the intent of the Apple macro - which was to encourage compatibility
> with GNU code. As I understand things Apple's __nonnull keyword used to
> mean something else but collided with GNU's __nonnull macro, so they
> renamed the keyword and put in a backward-compatibility macro for old
> Applish code, but we don't need that macro and can just use __nonnull
> for our own use.
>
> I attempted to fix the problem by installing the attached patch into
> Gnulib, and then merged Gnulib into Emacs master. Please give it a try,
> as I don't use macOS and so did not check the patch directly.

Thanks, it compiles fine for me now.