message: Try to fix Green Dragon bot.
  It doesn't like this std::tie() for some reason, hopefuly this
  fixes it.
diff: @@ -367,8 +367,8 @@ void PdbAstBuilder::BuildParentMap() {
  std::vector<TypeIndex> full_keys;
  std::vector<TypeIndex> fwd_keys;
  for (auto &entry : m_parent_types) {
  - TypeIndex key, value;
  - std::tie(key, value) = entry;
  + TypeIndex key = entry.first;
  + TypeIndex value = entry.second;
  auto iter = forward_to_full.find(value);
  if (iter != forward_to_full.end())
  