message: matc: log error when input material definition is empty
diff: @@ -261,6 +261,7 @@ bool MaterialCompiler::run(const Config& config) {
  Config::Input* input = config.getInput();
  ssize_t size = input->open();
  if (size <= 0) {
  + std::cerr << "Input file is empty" << std::endl;
  return false;
  }
  auto buffer = input->read();
  