message: fix VS Windows build with eigen.
diff: #include "opencv2/core.hpp"
  -#if EIGEN_WORLD_VERSION == 3 && EIGEN_MAJOR_VERSION >= 3 \
  - && defined(CV_CXX11) && defined(CV_CXX_STD_ARRAY)
  -#include <unsupported/Eigen/CXX11/Tensor>
  -#define OPENCV_EIGEN_TENSOR_SUPPORT
  -#endif // EIGEN_WORLD_VERSION == 3 && EIGEN_MAJOR_VERSION >= 3
  -
  #if defined _MSC_VER && _MSC_VER >= 1200
  +#define NOMINMAX // fix https://github.com/opencv/opencv/issues/17548
  #pragma warning( disable: 4714 ) //__forceinline is not inlined
  #pragma warning( disable: 4127 ) //conditional expression is constant
  #pragma warning( disable: 4244 ) //conversion from '__int64' to 'int', possible loss of data
  #endif
  +#if EIGEN_WORLD_VERSION == 3 && EIGEN_MAJOR_VERSION >= 3 \
  + && defined(CV_CXX11) && defined(CV_CXX_STD_ARRAY)
  +#include <unsupported/Eigen/CXX11/Tensor>
  +#define OPENCV_EIGEN_TENSOR_SUPPORT
  +#endif // EIGEN_WORLD_VERSION == 3 && EIGEN_MAJOR_VERSION >= 3
  +
  namespace cv
  {
  