diff --git a/library/dialect/swi.yap b/library/dialect/swi.yap
index 702938444..493fe0670 100644
--- a/library/dialect/swi.yap
+++ b/library/dialect/swi.yap
@@ -6,7 +6,6 @@
 :- module(system, [concat_atom/2,
 		   concat_atom/3,
 		   read_clause/1,
-		   string/1,
 		   chdir/1,
 		   compile_aux_clauses/1,
 		   convert_time/2,
@@ -15,8 +14,6 @@
 		   '$set_predicate_attribute'/3,
 		   stamp_date_time/3,
 		   date_time_stamp/2,
-		   format_time/3,
-		   format_time/4,
 		   time_file/2,
 		   flag/3,
 		   require/1,
@@ -96,6 +93,7 @@
 
 :- set_prolog_flag(user_flags,silent).
 
+
 % Time is given as a float in SWI-Prolog.
 swi_get_time(FSecs) :- datime(Datime),  mktime(Datime, Secs), FSecs is Secs*1.0.
 
@@ -157,8 +155,6 @@ concat_atom(List, New) :-
 read_clause(X,Y) :-
 	read_term(X,Y,[singetons(warning)]).
 
-string(_) :- fail.
-
 bindings_message(V) -->
        { cvt_bindings(V, Bindings) },
        prolog:message(query(_YesNo,Bindings)), !.
diff --git a/library/dialect/swi/fli/swi.c b/library/dialect/swi/fli/swi.c
index 53f1b5c05..b74f8bec7 100755
--- a/library/dialect/swi/fli/swi.c
+++ b/library/dialect/swi/fli/swi.c
@@ -160,7 +160,7 @@ X_API char* PL_atom_nchars(atom_t a, size_t *len)	 /* SAM check type */
 X_API term_t PL_copy_term_ref(term_t from)
 {
   CACHE_REGS
-  return YAP_InitSlot(Yap_GetFromSlot(from PASS_REGS));
+  return Yap_InitSlot(Yap_GetFromSlot(from PASS_REGS) PASS_REGS);
 }
 
 X_API term_t PL_new_term_ref(void)
@@ -182,7 +182,7 @@ X_API void PL_reset_term_refs(term_t after)
 {
   CACHE_REGS
   term_t new = Yap_NewSlots(1 PASS_REGS);
-  YAP_RecoverSlots(after-new);
+  Yap_RecoverSlots(after-new PASS_REGS);
 }
 
 /* begin PL_get_* functions =============================*/
diff --git a/library/matlab/Makefile.in b/library/matlab/Makefile.in
index e344fa6d8..a290f5a99 100644
--- a/library/matlab/Makefile.in
+++ b/library/matlab/Makefile.in
@@ -58,3 +58,6 @@ install: all
 clean:
 	rm -f *.o *~ $(OBJS) $(SOBJS) *.BAK
 
+realclean: clean
+	rm -f Makefile
+