Fix for libical >= 4

Index: libicalmapi/vevent.cpp
--- libicalmapi/vevent.cpp.orig
+++ libicalmapi/vevent.cpp
@@ -350,8 +350,8 @@ HRESULT VEventConverter::HrAddTimes(icalproperty_metho
 			return MAPI_E_INVALID_PARAMETER;
 
 		icaldurationtype dur = icalproperty_get_duration(lpicDurationProp);
-		timeDTEndLocal = timeDTStartLocal + icaldurationtype_as_int(dur);
-		timeDTEndUTC = timeDTStartUTC + icaldurationtype_as_int(dur);
+		timeDTEndLocal = timeDTStartLocal + icaldurationtype_as_utc_seconds(dur);
+		timeDTEndUTC = timeDTStartUTC + icaldurationtype_as_utc_seconds(dur);
 	}
 	timeEndOffset = timeDTEndUTC - timeDTEndLocal;
 	sPropVal.Value.ft = UnixTimeToFileTime(bIsAllday ? timeDTEndLocal : timeDTEndUTC);
