* [OpenCV] update to v4

* [OpenCV] update to v4.1

* [OpenCV] merge #6901 and #6812

* [OpenCV] port patches to v4.1

* [OpenCV] fix naming

* [OpenCV] fix regression with static linkage

* [OpenCV] fix linking to optional feature dependencies in static mode

* fix ffmpeg on some architectures

* trigger rebuild of regressions on macOS

* [zxing-cpp] fix opencv 4.1 compat

* [ogre] improve patching for static builds

* [OpenCV] fixes for extra features

* [OpenCV] drastically reduce patchset

* [OpenCV] fix regression on linux

* [OpenCV] fix regression on Windows

* [qt5] depends on qt5-activeqt only on windows

* update to v4.1.1

* [OpenCV] additional fixes for 4.1.1

* [OpenCV] fix Eigen3 feature integration

* [opencv] Fix compilation in UWP

* [opencv] Fix merge conflicts

* [ffmpeg] fix cmake module for osx

* [OpenCV] add pre-caching of optflow cuda package

* [gdcm] properly fix #6863 instead of wrong #6901

* [OpenCV] fix OpenMP feature

* [opencv] Add missing GetModuleHandle() call guard for UWP

* [freeimage] Do not depend on libwebp[all] on UWP

* [opencv] Set app container bit for UWP

* [zxing-cpp] Fail with explicit message in UWP

* [pthreads4w] fix target creation, missing dlls

* [pthreads4w] bump CONTROL

* [opencv,zxing-cpp] Fix OpenCV Video IO module

* [zxing-cpp] Revert unnecessary changes

* [opencv] Feature halide

* Fix regression in UWP

* [ffmpeg] remove unnecessary patch pointing to old OpenCV version

* [opencv] remove versioning from windows dll filenames

* [opencv] Move port to opencv4

* [opencv,opencv4] Make meta-package install OpenCV 4.1

* [opencv3] Rename old port opencv->opencv3

* Add failure messages when another OpenCV is already installed