Add handling of BYSETPOS for BYDAY in repeat rule

NEWS

@@ -1,6 +1,9 @@
 3.2.4 (2016-12-DD)
 ------------------
 
+Enhancements
+ - [core] added handling of BYSETPOS for BYDAY in recurrence rules
+
 Bug fixes
  - [web] fixed JavaScript exception when SOGo is launched from an external link (#3900)
  - [web] restored fetching of freebusy information of MS Exchange contacts

SOPE/NGCards/iCalRecurrenceRule.m

@@ -466,9 +466,16 @@ NSString *iCalWeekDayString[] = { @"SU", @"MO", @"TU", @"WE", @"TH", @"FR",
 
 - (iCalByDayMask *) byDayMask
 {
+  NSArray *setPos;
+  NSString *day;
+
   if (dayMask == nil && [[self byDay] length])
     {
-      dayMask = [iCalByDayMask byDayMaskWithRuleString: [self byDay]];
+      day = [self byDay];
+      setPos = [self bySetPos];
+      if ([setPos count])
+        day = [NSString stringWithFormat: @"%@%@", [setPos lastObject], day];
+      dayMask = [iCalByDayMask byDayMaskWithRuleString: day];
       [dayMask retain];
     }