Try to clarify operators

prolog has priority and cannot be redefined by default.
user is global but may be redefined
others should just plug-in.

C/modules.c

@@ -52,6 +52,7 @@ initMod( AtomEntry *toname, AtomEntry *ae) {
     n->KindOfPE = ModProperty;
     n->PredForME = NULL;
     n->NextME = CurrentModules;
+    n->ParentForME = CurrentModule;
     CurrentModules = n;
     n->AtomOfME = ae;
     n->OwnerFile = Yap_ConsultingFile( PASS_REGS1);
@@ -259,7 +260,6 @@ static Int change_module(USES_REGS1) { /* $change_module(N)		 */
   Term mod = Deref(ARG1);
   LookupModule(mod);
   CurrentModule = mod;
-  LOCAL_SourceModule = mod;
   return TRUE;
 }