Linux平台下使用CMAKE3.10.2与CUDA10.2混合编程时出现错误：
“Missing variable is:CMAKE_CUDA_DEVICE_LINK_EXECUTABLE”
根据https://github.com/colmap/colmap/issues/1590
在主文件夹C++ CmakeLists.txt中添加如下代码后成功构建。
if(NOT DEFINED CMAKE_CUDA_STANDARD)
set(CMAKE_CXX_STANDARD 17)
set(CMAKE_CUDA_STANDARD 14)
set(CMAKE_CUDA_STANDARD_REQUIRED TRUE)
set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
endif()
enable_language(CUDA)
