Only use this feature when building for 1 or 2 CUDA architectures.
Otherwise CMake will build the binaries in parallel, and NVCC will then
also launch multiple threads for each binary.
We could add more manual control for this, but the main use case for
this is local builds and an automatic heuristic seems more likely to
help than an option that developers or users might not discover.
For minimal memory usage WITH_CYCLES_CUDA_BUILD_SERIAL still exists
to use only 1 thread for CUDA compilation.
Pull Request: https://projects.blender.org/blender/blender/pulls/147303
74b7d663e1