message: Fixes GCC warning(error).
diff: @@ -148,8 +148,10 @@ void parseInputMapping(Config& _config, YAML::Node const& _mapping)
  auto const name = toLower(_node.as<string>());
  for (auto const& mapping : mappings)
  + {
  if (name == toLower(mapping.first))
  return mapping.second;
  + }
  return nullopt;
  };
  