message: cmake: prefer using Eigen configuration files
  for better compatibility with Ceres 2.0.0 CMake scripts
diff: @@ -51,7 +51,12 @@ endif(WITH_CUDA)
  # --- Eigen ---
  if(WITH_EIGEN AND NOT HAVE_EIGEN)
  + if(NOT OPENCV_SKIP_EIGEN_FIND_PACKAGE_CONFIG)
  + find_package(Eigen3 CONFIG QUIET) # Ceres 2.0.0 CMake scripts doesn't work with CMake's FindEigen3.cmake module (due to missing EIGEN3_VERSION_STRING)
  + endif()
  + if(NOT Eigen3_FOUND)
  find_package(Eigen3 QUIET)
  + endif()
  if(Eigen3_FOUND)
  if(TARGET Eigen3::Eigen)
  