现代cmake下运行cuda程序

主要是抛弃find而转向通用的set方法，具体参考了：

modern-cmake tutorial： https://cliutils.gitlab.io/modern-cmake/chapters/packages/CUDA.html

Building Cross-Platform CUDA Applications with CMake: https://developer.nvidia.com/blog/building-cuda-applications-cmake/

A good resource for CUDA and Modern CMake is this talk by CMake developer Robert Maynard at GTC 2017.

Adding the CUDA Language

There are two ways to enable CUDA support.

project(MY_PROJECT LANGUAGES CUDA CXX)

if CUDA is optional, you'll want to put this in somewhere conditionally:

enable_language(CUDA)