diff -pNaru5 a/objectcache.hh b/objectcache.hh
--- a/objectcache.hh	2020-06-07 11:35:57.000000000 -0400
+++ b/objectcache.hh	2024-01-01 23:03:39.196822579 -0500
@@ -64,11 +64,11 @@ private:
   };
   typedef std::list< Object > Objects;
 
   struct ObjectsIteratorComp
   {
-    bool operator () ( Objects::iterator const & x, Objects::iterator const & y )
+    bool operator () ( Objects::iterator const & x, Objects::iterator const & y ) const
     { return x->id < y->id; }
   };
 
   typedef std::set< Objects::iterator, ObjectsIteratorComp > ObjectMap;