ENH: package a pkg-config console entry-point for windows

[mattip]

Over at numpy/numpy#30189 I tried to replace the choco download of pkgconfiglite on windows with a pur-python alternative. It turns out that package is broken.

It got me thinking: what if we packaged a console entry-point script pkg-config with this package. We already have the proper get_pkg_config() output, so most of the work would be to

• create a command line parser using argparse
• turn __main__ into a console script entry point in pyproject.toml
• If pkg-config is on thePATH, passthrough to it.
• If scipy-openblas is not the library name, error out as-if pkg-config is not found
• Handle just enough command-line arguments to make meson happy.

This would simplify building on windows: if this package is installed, no additional pkg-config executable would be needed.

Another option would be to add a custom meson Dependency class for scipy-openblas, but the problem is in the initial BLAS/LAPACK detection logic, how do we specify that the package exists?

[rgommers]

what if we packaged a console entry-point script pkg-config with this package.

+1 for that, but then the entrypoint for https://github.com/pypackaging-native/pkgconf-pypi/ just like numpy already has:

https://github.com/numpy/numpy/blob/8b8653c6d2e70e72912cbc247317507495abbacf/pyproject.toml#L90-L91

That makes most of the above bullet points obsolete I think, just needs the first two?

[mattip]

Ahh, cool. Then we could use the same prefix=${pcfiledir}/.. to avoid all the get_pkgconfig_file work-arounds to mangle the paths and create a *pc file in CI. That would require NumPy and Scipy to add pkgconf to the build dependencies, right?

[rgommers]

Indeed, it would avoid that dance.

That would require NumPy and Scipy to add pkgconf to the build dependencies, right?

Not to the build dependencies in pyproject.toml, just in the wheel build jobs in CI.

For pyproject.toml, working towards doing it actually correctly/completely like so: https://peps.python.org/pep-0725/#scipy-1-10