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

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

Thomas Klausner <wiz%netbsd.org@localhost> writes:

> On Fri, Aug 14, 2026 at 07:26:26AM +0100, Benny Siegert wrote:

>> Should we make the textproc/expat builtin check also verify that
>> expat_config.h is present? That would solve the problem once and for all.

> The advantage is that it would fix Python because that unconditionally
> looks for expat_config.h.
>
> The disadvantage is that it's not required for most other software,
> and we would stop allowing built-in expat on NetBSD < 11.99.5 (before
> expat_config.h was installed).

As a middle ground, we could add some

	EXPAT_REQUIRED_FEATURES+=	expat_config.h

to python's makefile, and have builtin.mk reject implementations without
the file, when that variable is present.   That would be a clean way to
get new expat for python without forcing all others.

Alternatively and likely better, the addition of expat_config is an API
change, and python should be able to set an bl3 API_DPENDS variable to
require new enough

I see Jonathan's point about constructing one, but python requires
newish expat, and I tend to just roll with that vs struggling against
it.