* [OpenCV2] add library for older C projects
* [OpenCV2] fixes for non-Windows systems
* [OpenCV2] add warnings for Ubuntu
* add fixes for cuda
* [OpenCV2] disable parallel building, otherwise cuda fails
* [OpenCV2] refresh port with latest fixes
* [OpenCV2] fix CONTROL
* [OpenCV2] fixes for windows
* [OpenCV2] fixes to avoid unnecessary install of pre-built ffmpeg, since it already uses externally provided one
* [OpenCV2] openexr still has some problems, explicitly removed UWP support
* [OpenCV2] use targets wherever possible. Jasper and OpenEXR features would require improvements in those ports, in order for them to provide targets too
* [OpenCV2] re-enable parallel build also with CUDA
* [OpenCV2] improve compatibility with CUDA 10+
* [OpenCV2] fix broken CUDA targets
* [darknet] enable opencv2 feature
* skip from building, like opencv3, to avoid problems in CI
