Free-threaded (i.e. no-GIL) Python support

[Michal Szolucha PL]

Hi,

Late last year, PEP 703 got approved which proposes to remove the GIL from Python. The timeline is pretty far, however Python 3.13alpha is already available where the GIL might be turned off. I've tried building CuPy for the Python3.13a and stumbled upon the `fastrlock` dependency, which actually relies on GIL existence.

I'm wondering, is there any plan to remove the fastrlock dependency? Alternatively, is there a plan of support of the free-threaded Python?

MS