Scikit-build (classic) 1.0 internals #8799

Hi,

I'm currently working on swapping out scikit-build (classic)'s internals for scikit-build-core, and I have AI running lots of downstream projects and looking for regressions. It found that this project currently uses scikit-build internals. I've been able to patch some of them back in as shims, but taichi uses command.*, which has been deprecated by setuptools for years and we don't support that with the new internals. You are also using constants.CMAKE_BUILD_DIR and/or set_skbuild_plat_name, which are no longer supported either. I might be able to shim CMAKE_BUILD_DIR if really needed.

See scikit-build/scikit-build#1185. I can try to propose something here if you'd like. The best thing would be to use scikit-build-core without setuptools directly.