Support timezone West of UTC (thanks to Edwin Fine)(EJAB-1301)

src/mod_time.erl

@@ -59,7 +59,13 @@ process_local_iq(_From, _To, #iq{type = get} = IQ_Rec) ->
 	    {UTC, UTC_diff} = jlib:timestamp_to_iso(Now_universal, utc),
 	    Seconds_diff = calendar:datetime_to_gregorian_seconds(Now_local)
 	     - calendar:datetime_to_gregorian_seconds(Now_universal),
-	    {Hd, Md, _} = calendar:seconds_to_time(Seconds_diff),
+            {Hd, Md, _} = case Seconds_diff >= 0 of
+			      true ->
+				  calendar:seconds_to_time(Seconds_diff);
+			      false ->
+				  {Hd0, Md0, Sd0} = calendar:seconds_to_time(-Seconds_diff),
+				  {-Hd0, Md0, Sd0}
+			  end,
 	    {_, TZO_diff} = jlib:timestamp_to_iso({{0, 0, 0}, {0, 0, 0}}, {Hd, Md}),
     Result = #xmlel{ns = ?NS_TIME, name = 'time', children = [
 	    	#xmlel{ns = ?NS_TIME, name = 'tzo', children = [