Update to get 6model core to build agian.

Author: jnthn

src/6model/knowhow_bootstrapper.c

@@ -184,7 +184,7 @@ PMC * SixModelObject_bootstrap_knowhow(PARROT_INTERP, PMC *sc) {
     /* We create a KnowHOW instance that can describe itself. This means
      * .HOW.HOW.HOW.HOW etc will always return that, which closes the model
      * up. Also pull out its underlying struct. */
-    PMC *knowhow_how_pmc = REPR->allocate(interp, PMCNULL);
+    PMC *knowhow_how_pmc = REPR->allocate(interp, NULL);
     KnowHOWREPRInstance *knowhow_how = (KnowHOWREPRInstance *)PMC_data(knowhow_how_pmc);
 
     /* Need to give the knowhow_how a twiddled STable with a different
@@ -261,7 +261,7 @@ static void attr_new(PARROT_INTERP, PMC *nci) {
     PMC    *type    = VTABLE_get_pmc_keyed_int(interp, capture, 0);
     STRING *name    = VTABLE_get_string_keyed_str(interp, capture, name_str);
     PMC    *self    = REPR(type)->allocate(interp, STABLE(type));
-    REPR(self)->set_str(interp, STABLE(self), OBJECT_BODY(self), name);
+    REPR(self)->box_funcs->set_str(interp, STABLE(self), OBJECT_BODY(self), name);
     unused = Parrot_pcc_build_call_from_c_args(interp, capture, "P", self);
 }
 
@@ -270,7 +270,7 @@ static void attr_name(PARROT_INTERP, PMC *nci) {
     PMC * unused;
     PMC    *capture = Parrot_pcc_get_signature(interp, CURRENT_CONTEXT(interp));
     PMC    *self    = VTABLE_get_pmc_keyed_int(interp, capture, 0);
-    STRING *name    = REPR(self)->get_str(interp, STABLE(self), OBJECT_BODY(self));
+    STRING *name    = REPR(self)->box_funcs->get_str(interp, STABLE(self), OBJECT_BODY(self));
     unused = Parrot_pcc_build_call_from_c_args(interp, capture, "S", name);
 }