Re: Python 3.13 fails to build under macOS, expat issue

[Greg Troxel <gdt%lexort.com@localhost>]

Jonathan Perkin <jperkin%pkgsrc.org@localhost> writes:

> * On 2026-08-14 at 10:30 BST, Benny Siegert wrote:
>
>> What do you propose? I can just disable builtin expat on Darwin, but
>> that feels like a hack.
>
> Remember that Apple have fundamentally broken builtins.  It is now
> impossible, for example, to ensure that check-shlibs works correctly,
> given they no longer ship the actual e.g. /usr/lib/libexpat.dylib file
> and instead you have to rely on some weird virtual library cache.
>
> You also have the added complications of the headers coming from the
> target SDK version and not what's installed on the host system.
>
> It is definitely not a hack to PREFER_PKGSRC=yes on modern Darwin.  I
> would argue it's the correct choice, and use it on all my systems and
> published package repositories.

If you want to change the defaults on Darwin to say "we can't reliably
figure out if foo is ok, so assume it isn't and prefer pkgsrc", I don't
have a problem with that.   That's a separable issue from coping with
expat's oddness of installing private headers and other programs using
them.