PyLong_FromLong() doesn't go into the 1 digit special case for 
negative number. You should use:
	/* Fast path for single-digits ints */
	if (!(abs_ival>>PyLong_SHIFT)) {
		v = _PyLong_New(1);
		if (v) {
			Py_SIZE(v) = sign;
			v->ob_digit[0] = abs_ival;
		}
		return (PyObject*)v;
	}