message: C++17: SimpleAtoi -> absl::SimpleAtoi (missing absl::)
  This has worked so far due to ADL (argument-dependent lookup): the
  string_view argument causes the absl:: namespace to be considered.
  When std::string_view is available, the Abseil string_view might just be a
  'using' alias to it; ADL no longer applies.
diff: @@ -118,7 +118,7 @@ bool Arg<toco::IntList>::Parse(string text) {
  if (!text.empty()) {
  int32 element;
  for (absl::string_view part : absl::StrSplit(text, ',')) {
  - if (!SimpleAtoi(part, &element)) return false;
  + if (!absl::SimpleAtoi(part, &element)) return false;
  parsed_value_.elements.push_back(element);
  }
  }
  