Building cuda.bindings in parallel might fail non-deterministically

[leofang]

Our new CI (#267) immediately exposes a longstanding, widely known setuptools/distutils issue when PARALLEL_LEVEL is set, xref:

• https://github.com/NVIDIA/cuda-python/actions/runs/12192916020/job/34014323275#step:4:2187

    D:\a\cuda-python\cuda-python\cuda_bindings\cuda\bindings\_bindings\loader.cpp : fatal error C1083: Cannot open compiler generated file: 'D:\a\cuda-python\cuda-python\cuda_bindings\build\temp.win-amd64-cpython-310\Release\cuda\bindings\_bindings\loader.obj': Permission denied

• [BUG] setuptools does not protect against race conditions on parallel builds pypa/setuptools#3119
• [BUG] Pararell builds result in different module content pypa/setuptools#3942
• Debug build on Windows fails without -j1 pypa/setuptools#2442
• Unable to build in parallel with Python 3 scipy/scipy#7112

[leofang]

tl;dr for the above threads is: The way that we build/link the same .c/.cpp file to multiple shared extension modules, i.e.,

cuda-python/cuda_bindings/setup.py

Lines 267 to 268 in 60f9362

	# private
	["cuda/bindings/_bindings/*.pyx", "cuda/bindings/_bindings/loader.cpp"],

is the root cause, as it triggers setuptools's race condition (which is a bug that would unlikely be fixed).

[leofang]

Bumping this to P0 as it now shows up in virtually every single (build) CI runs. @vzhurba01 please prioritize for fixing issues caught by the CI. Thanks!