message: Restore previous unwind_state.
diff: @@ -44,6 +44,8 @@ void catch_unwind(std::function<void()> &&f) {
  unwind_state = &current;
  unwinding_setjmp(current.stack, unwind_payload, (void *)&current);
  +
  + unwind_state = current.prev;
  if (current.exception) {
  throw *current.exception;
  }
  