message: cmake: cl2cpp change main OUTPUT to .hpp file
  To reduce number of unnecessary rebuilds on updates of OpenCL kernels
diff: @@ -720,7 +720,7 @@ macro(ocv_glob_module_sources)
  if(cl_kernels)
  set(OCL_NAME opencl_kernels_${name})
  add_custom_command(
  - OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/${OCL_NAME}.cpp" "${CMAKE_CURRENT_BINARY_DIR}/${OCL_NAME}.hpp"
  + OUTPUT "${CMAKE_CURRENT_BINARY_DIR}/${OCL_NAME}.hpp" "${CMAKE_CURRENT_BINARY_DIR}/${OCL_NAME}.cpp"
  COMMAND ${CMAKE_COMMAND} "-DMODULE_NAME=${name}" "-DCL_DIR=${CMAKE_CURRENT_LIST_DIR}/src/opencl" "-DOUTPUT=${CMAKE_CURRENT_BINARY_DIR}/${OCL_NAME}.cpp" -P "${OpenCV_SOURCE_DIR}/cmake/cl2cpp.cmake"
  DEPENDS ${cl_kernels} "${OpenCV_SOURCE_DIR}/cmake/cl2cpp.cmake")
  ocv_source_group("Src\\opencl\\kernels" FILES ${cl_kernels})
  