Fix compiler warning

Python/gc.c

@@ -1233,7 +1233,7 @@ gc_collect_region(PyThreadState *tstate,
                   struct gc_collection_stats *stats);
 
 static inline Py_ssize_t
-gc_list_set_space(PyGC_Head *list, uintptr_t space)
+gc_list_set_space(PyGC_Head *list, int space)
 {
     Py_ssize_t size = 0;
     PyGC_Head *gc;