diff --git a/C/tracer.c b/C/tracer.c
index e077ccbc3..a5e583670 100644
--- a/C/tracer.c
+++ b/C/tracer.c
@@ -161,6 +161,7 @@ low_level_trace(yap_low_level_port port, PredEntry *pred, CELL *args)
   LOCK(Yap_heap_regs->low_level_trace_lock);
   sc = Yap_heap_regs;
   vsc_count++;
+  return;
 #ifdef COMMENTED
   if (vsc_count > 1388060LL && vsc_count < 1388070LL) {
     if (vsc_count==1388061LL)
diff --git a/changes-5.1.html b/changes-5.1.html
index ab0869f89..b4e774535 100644
--- a/changes-5.1.html
+++ b/changes-5.1.html
@@ -16,6 +16,8 @@
 
 <h2>Yap-5.1.2:</h2>
 <ul>
+<li> FIXED: mktime needs to know if daylight time savings are on
+(obs from Bernd Gutmann).</li>
 <li> FIXED: handle atom lookup and functor overflows while parsing
 (obs from Bernd Gutmann).</li>
 <li> FIXED: get rid of static structures for modules (obs from Bernd
diff --git a/library/system/sys.c b/library/system/sys.c
index cce6f9586..38eeb2cf2 100644
--- a/library/system/sys.c
+++ b/library/system/sys.c
@@ -8,8 +8,11 @@
 *									 *
 **************************************************************************
 *									 *
-* $Id: sys.c,v 1.30 2007-05-02 11:16:43 vsc Exp $									 *
+* $Id: sys.c,v 1.31 2007-05-07 11:21:29 vsc Exp $									 *
 * mods:		$Log: not supported by cvs2svn $
+* mods:		Revision 1.30  2007/05/02 11:16:43  vsc
+* mods:		small fixes to sys.c
+* mods:		
 * mods:		Revision 1.29  2006/10/10 14:08:17  vsc
 * mods:		small fixes on threaded implementation.
 * mods:		
@@ -186,6 +189,7 @@ sysmktime(void)
   loc.tm_hour = YAP_IntOfTerm(YAP_ARG4);
   loc.tm_min = YAP_IntOfTerm(YAP_ARG5);
   loc.tm_sec = YAP_IntOfTerm(YAP_ARG6);
+  loc.tm_isdst = -1;
 
   if ((tim = mktime(&loc)) < 0) {
     return YAP_Unify(YAP_ARG8, YAP_MkIntTerm(errno));