message: Mipgen now creates the out dir if needed.
diff: @@ -338,6 +338,7 @@ int main(int argc, char* argv[]) {
  }
  vector<uint8_t> fileContents(container.getSerializedLength());
  container.serialize(fileContents.data(), fileContents.size());
  + Path(outputPattern).getParent().mkdirRecursive();
  ofstream outputStream(outputPattern, ios::out | ios::binary);
  outputStream.write((const char*) fileContents.data(), fileContents.size());
  outputStream.close();
  @@ -354,6 +355,7 @@ int main(int argc, char* argv[]) {
  cerr << "Output pattern is too long." << endl;
  return 1;
  }
  + Path(path).getParent().mkdirRecursive();
  ofstream outputStream(path, ios::binary | ios::trunc);
  if (!outputStream) {
  cerr << "The output file cannot be opened: " << path << endl;
  