Description:
I would like to add support for installing GraalPy via setup-python. We are starting to ask people to include support for GraalPy in their packages, and they (reasonably) request to be able to test against GraalPy using their existing workflows using setup-python.

Are you willing to submit a PR?
I have prepared the changes for setup-python, mimicking the PyPy support code. The tests using local mock data pass.