Issue #22156: Fix "comparison between signed and unsigned integers" compiler
warnings in the Objects/ subdirectory.

PyType_FromSpecWithBases() and PyType_FromSpec() now reject explicitly negative
slot identifiers.
diff --git a/Objects/setobject.c b/Objects/setobject.c
index dff1597..8f7542c 100644
--- a/Objects/setobject.c
+++ b/Objects/setobject.c
@@ -771,7 +771,7 @@
     /* Make the final result spread-out in a different pattern
        than the algorithm for tuples or other python objects. */
     hash = hash * 69069U + 907133923UL;
-    if (hash == -1)
+    if (hash == (Py_uhash_t)-1)
         hash = 590923713UL;
     so->hash = hash;
     return hash;