Fix wrong #ifdef.
diff --git a/Objects/stringobject.c b/Objects/stringobject.c
index cceed75..40cd15a 100644
--- a/Objects/stringobject.c
+++ b/Objects/stringobject.c
@@ -306,7 +306,7 @@
 		return -1;
 	}
 	/* XXX UNREF/NEWREF interface should be more symmetrical */
-#ifdef TRACE_REFS
+#ifdef REF_DEBUG
 	--ref_total;
 #endif
 	UNREF(v);