fix slice cache finalization to use gc del
diff --git a/Objects/sliceobject.c b/Objects/sliceobject.c
index bf5eb3a..2f32355 100644
--- a/Objects/sliceobject.c
+++ b/Objects/sliceobject.c
@@ -102,7 +102,7 @@
     PySliceObject *obj = slice_cache;
     if (obj != NULL) {
         slice_cache = NULL;
-        PyObject_Del(obj);
+        PyObject_GC_Del(obj);
     }
 }