message: python: eliminate -Wundef warning about NPY_INTERNAL_BUILD
  numpy 1.13.0+
diff: @@ -118,6 +118,7 @@ if(MSVC AND NOT ENABLE_NOISY_WARNINGS)
  endif()
  ocv_warnings_disable(CMAKE_CXX_FLAGS -Woverloaded-virtual -Wunused-private-field)
  +ocv_warnings_disable(CMAKE_CXX_FLAGS -Wundef) # accurate guard via #pragma doesn't work (C++ preprocessor doesn't handle #pragma)
  if(MSVC AND NOT BUILD_SHARED_LIBS)
  set_target_properties(${the_module} PROPERTIES LINK_FLAGS "/NODEFAULTLIB:atlthunk.lib /NODEFAULTLIB:atlsd.lib /DEBUG")
  