* Fix libpath logic for Windows (#9687)
* Use sys.base_prefix instead of sys.prefix (#9711)
* Use sys.base_prefix instead of sys.prefix
* Update libpath.py too
* Create pyproject.toml
* Implement a custom build backend (see below) in packager directory. Build logic from setup.py has been refactored and migrated into the new backend.
* Tested: pip wheel . (build wheel), python -m build --sdist . (source distribution)
