message: cmake: eliminate GCC4.x warnings
diff: @@ -132,6 +132,9 @@ if(CV_GCC OR CV_CLANG)
  if(CV_GCC AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 7.0)
  add_extra_compiler_option(-Wno-strict-overflow) # Issue appears when compiling surf.cpp from opencv_contrib/modules/xfeatures2d
  endif()
  + if(CV_GCC AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.0)
  + add_extra_compiler_option(-Wno-missing-field-initializers) # GCC 4.x emits warnings about {}, fixed in GCC 5+
  + endif()
  endif()
  add_extra_compiler_option(-fdiagnostics-show-option)
  