Merge pull request #14177 from alalek:fix_14173

modules/core/CMakeLists.txt

@@ -35,6 +35,9 @@ if(DEFINED WINRT AND NOT DEFINED ENABLE_WINRT_MODE_NATIVE)
 endif()
 
 if(HAVE_CUDA)
+  if(NOT TARGET opencv_cudev)
+    message(FATAL_ERROR "CUDA: OpenCV requires enabled 'cudev' module from 'opencv_contrib' repository: https://github.com/opencv/opencv_contrib")
+  endif()
   ocv_warnings_disable(CMAKE_CXX_FLAGS -Wundef -Wenum-compare -Wunused-function -Wshadow)
 endif()