message: Fix tensorflow::CurrentStackTrace when TF_GENERATE_BACKTRACE isn't defined
diff: @@ -66,6 +66,8 @@ inline std::string CurrentStackTrace() {
  ss << "*** End stack trace ***" << std::endl;
  return ss.str();
  +#else
  + return std::string();
  #endif // defined(TF_GENERATE_BACKTRACE)
  }
  