now it builds by the command:
`cmake.exe -Wno-dev -GNinja -DCMAKE_MAKE_PROGRAM="path\to\ninja\ninja.exe" -DCMAKE_TOOLCHAIN_FILE=../opencv3/platforms/android/android.toolchain.cmake -DANDROID_ABI="armeabi-v7a with NEON" -DANDROID_SDK_TARGET=21 -DANDROID_NATIVE_API_LEVEL=14 -DCMAKE_BUILD_WITH_INSTALL_RPATH=ON -DBUILD_ANDROID_EXAMPLES=ON -DINSTALL_ANDROID_EXAMPLES=ON -DWITH_OPENCL=YES -DANDROID_OPENCL_SDK=path\to\OpenCL ../opencv`