This is useful if, for example, you want ccache to be used for nvcc. With the current behavior, cmake always picks up /usr/local/cuda/bin/nvcc, even if there is a ccache nvcc stub in the PATH. Allowing for CUDA_NVCC_EXECUTABLE lets us work around the problem.
Signed-off-by: Edward Z. Yang ezyang@fb.com
Topic-rename: FindCUDA-nvcc-executable-env