This is VS2017 Preview. It makes sure the version is detected properly and the INSTALL target then correctly installs to x64/vc15 (the same as MSVC1910).
Without the fix, OpenCV will compile and silently copy the compiled libs/executables to a location not prefixed with arch/vc14, and OpenCV won't be picked up by find_package and OpenCVConfig.cmake.
MinGW-w64 always uses "w64" as vendor key which the previously
used check for "64" anywhere in the target triplet matched. This
would lead to MinGW-w64 setups always being treated as x64.
Since we are actually interested in finding the "64" in the
triplet's operating system key, this fix makes sure to look for
"mingw64" and thus avoids the false match.
Fixes issue #3835. Credits to Lode Leroy for the original patch.
To speed up rebuilds, define the NDK_CCACHE environment or CMake variable
to the path to your ccache binary. When declared, the android.cmake.toolchain
automatically uses CCache when compiling any C/C++ source file. For example:
export NDK_CCACHE=ccache
[~] Automatically tracked dependencies between modules
[+] Support for optional module dependencies
[+] Options to choose modules to build
[~] Removed hardcoded modules lists from OpenCVConfig.cmake, opencv.pc and OpenCV.mk
[+] Added COMPONENTS support for FIND_PACKAGE(OpenCV)
[~] haartraining and traincascade are moved outside of modules folder since they aren't the modules