FindCUDAToolkit: Handle toolkits that don't provide nvptxcompiler
requested to merge robertmaynard/cmake:FindCUDAToolkit_handle_nvptxcompiler_static_not_existing into master
Some versions of the CUDA toolkit don't provide any static
libraries, and therefore we need to handle that nvptxcompiler_static
might not be found.
Backport: release
Edited by Brad King