message: Remove directory stack var
diff: @@ -327,7 +327,6 @@ impl<'a> Variables<'a> {
  impl<'a> Default for Variables<'a> {
  fn default() -> Self {
  let mut map: Scopes<types::Str, Value<'a>> = Scopes::with_capacity(64);
  - map.set("DIRECTORY_STACK_SIZE", "1000");
  map.set("HISTORY_SIZE", "1000");
  map.set("HISTFILE_SIZE", "100000");
  map.set(
  