Repair two TIME WITH TIME ZONE bugs found by Dennis Vshivkov. Comparison

of timetz values misbehaved in --enable-integer-datetime cases, and
EXTRACT(EPOCH) subtracted the zone instead of adding it in all cases.
Backpatch to all supported releases (except --enable-integer-datetime code
does not exist in 7.2).

src/backend/utils/adt/date.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/date.c,v 1.104 2004/12/31 22:01:21 pgsql Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/date.c,v 1.105 2005/04/23 22:53:05 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1869,12 +1869,20 @@ timetz_scale(PG_FUNCTION_ARGS)
 static int
 timetz_cmp_internal(TimeTzADT *time1, TimeTzADT *time2)
 {
+	/* Primary sort is by true (GMT-equivalent) time */
+#ifdef HAVE_INT64_TIMESTAMP
+	int64		t1,
+				t2;
+
+	t1 = time1->time + (time1->zone * INT64CONST(1000000));
+	t2 = time2->time + (time2->zone * INT64CONST(1000000));
+#else
 	double		t1,
 				t2;
 
-	/* Primary sort is by true (GMT-equivalent) time */
 	t1 = time1->time + time1->zone;
 	t2 = time2->time + time2->zone;
+#endif
 
 	if (t1 > t2)
 		return 1;
@@ -2443,9 +2451,9 @@ timetz_part(PG_FUNCTION_ARGS)
 	else if ((type == RESERV) && (val == DTK_EPOCH))
 	{
 #ifdef HAVE_INT64_TIMESTAMP
-		result = ((time->time / 1000000e0) - time->zone);
+		result = ((time->time / 1000000e0) + time->zone);
 #else
-		result = (time->time - time->zone);
+		result = (time->time + time->zone);
 #endif
 	}
 	else