CI is passing. I think it is fine for now to leave installing it as part of the CI environment, since we also assume there is a pkg-config available in posix builds. We don't explicitly mention how to install pkg-config in the building page. We do mention it in passing as part of the ""conda env" tab.

Edit: actually, the wheel workflow failed but gave no indication of a problem ☹️

The numpy-release builds use also use choco to install pkgconfiglite, I'm guessing cibuildwheel requires it.

Bleh. The package does not work, it seems I was misled by a package installed with perl on the windows images. Closing

A possible improvement would be to add pykg-config as a build requirement.

This is now moot, but: we shouldn't do that so easily, it's not a Python package and it's not needed for almost all build scenarios.

This PR reminded me of gh-26574, which we really should find some time to finish. Might need a Christmas holiday ....