[Python-Dev] check for PyUnicode_READY look backwards

["Martin v. Löwis"]

  > if (!PyUnicode_READY(foo)) is not better, also because of
> PyUnicode_IS_READY(foo).
>
> I prefer PyUnicode_IS_READY(foo) < 0 over PyUnicode_IS_READY(foo) == -1.
>

Ok, so feel free to replace all == -1 tests with < 0 tests as well.

I'll point out that the test for -1 is also widespread in Python,
e.g. when checking return values from PyObject_SetAttrString,
BaseException_init, PyThread_create_key, PyObject_DelAttrString, etc.

Regards,
Martin