Fixed error introduced in the initial implementation of

mu_mktime (now mu_tm2time). The comment on mu_tm2time() describes it.
Revert the sign of the return value of mu_utc_offset(), so it
agrees with the accepted timezone rules (+ for eastern
hemisphere, - for western).

@@ -31,23 +31,30 @@
  
  
  mktime() always treats tm as if it was localtime, so convert it
  mktime() always treats tm as if it was localtime, so convert it
  to UTC, then adjust by the tm's real timezone, if it is known.
  to UTC, then adjust by the tm's real timezone, if it is known.
+ 
+ NOTE: 1. mktime converts localtime struct tm to *time_t in UTC*
+       2. adding mu_utc_offset() compensates for the localtime
+          corrections in in mktime(), i.e. it yields the time_t in
+	  the current zone of struct tm.
+       3. finally, subtracting TZ offset yields the UTC.
 */
 */
 time_t
 time_t
 mu_tm2time (struct tm *timeptr, mu_timezone* tz)
 mu_tm2time (struct tm *timeptr, mu_timezone* tz)
 {
 {
   int offset = tz ? tz->utc_offset : 0;
   int offset = tz ? tz->utc_offset : 0;
   
   
-  return mktime(timeptr) - mu_utc_offset() + offset;
+  return mktime(timeptr) + mu_utc_offset() - offset;
 }
 }
 
 
 /* Convert time 0 at UTC to our localtime, that tells us the offset
 /* Convert time 0 at UTC to our localtime, that tells us the offset
    of our current timezone from UTC. */
    of our current timezone from UTC. */
-time_t mu_utc_offset(void)
+time_t
+mu_utc_offset(void)
 {
 {
   time_t t = 0;
   time_t t = 0;
   struct tm* tm = gmtime(&t);
   struct tm* tm = gmtime(&t);
 
 
-  return mktime(tm);
+  return - mktime(tm);
 }
 }
 
 
 static const char *months[] =
 static const char *months[] =