message: convert path to string
diff: @@ -175,9 +175,9 @@ namespace vcpkg
  out_str.append(Strings::join(",",
  Util::fmap(
  pgh.external_files,
  - [](const std::pair<std::string, std::string>& kv)
  + [](const std::pair<fs::path, std::string>& kv)
  {
  - return kv.first + "," + kv.second;
  + return kv.first.u8string() + "," + kv.second;
  }))).push_back('\n');
  }
  }
  