message: format_args! requires at least one argument
  fix macro to guarantee the required behavior
diff: @@ -18,7 +18,7 @@ macro_rules! align_up {
  /// for HermitCore.
  #[macro_export]
  macro_rules! print {
  - ($($arg:tt)*) => ($crate::_print(::core::format_args!($($arg)*)));
  + ($($arg:tt)+) => ($crate::_print(::core::format_args!($($arg)+)));
  }
  /// Print formatted text to our console, followed by a newline.
  