Allow long integers in PySlice_GetIndices.

Objects/sliceobject.c

@@ -106,20 +106,20 @@ PySlice_GetIndices(PySliceObject *r, Py_ssize_t length,
 	if (r->step == Py_None) {
 		*step = 1;
 	} else {
-		if (!PyInt_Check(r->step)) return -1;
+		if (!PyInt_Check(r->step) && !PyLong_Check(r->step)) return -1;
 		*step = PyInt_AsSsize_t(r->step);
 	}
 	if (r->start == Py_None) {
 		*start = *step < 0 ? length-1 : 0;
 	} else {
-		if (!PyInt_Check(r->start)) return -1;
+		if (!PyInt_Check(r->start) && !PyLong_Check(r->step)) return -1;
 		*start = PyInt_AsSsize_t(r->start);
 		if (*start < 0) *start += length;
 	}
 	if (r->stop == Py_None) {
 		*stop = *step < 0 ? -1 : length;
 	} else {
-		if (!PyInt_Check(r->stop)) return -1;
+		if (!PyInt_Check(r->stop) && !PyLong_Check(r->step)) return -1;
 		*stop = PyInt_AsSsize_t(r->stop);
 		if (*stop < 0) *stop += length;
 	}