Datetime regression tests are all failing

Your last commit seems to have broken timestamp, interval, reltime,
and horology regress tests on HPUX. Minus signs are showing up in
a lot of unexpected-looking places, eg

*** ./expected/timestamp.out Sat Nov 25 11:05:59 2000
--- ./results/timestamp.out Thu Jan 18 01:28:28 2001
***************
*** 631,638 ****
SELECT '' AS "53", d1 - timestamp '1997-01-02' AS diff
FROM TIMESTAMP_TBL WHERE d1 BETWEEN '1902-01-01' AND '2038-01-01';
53 | diff
! ----+----------------------------------------
! | @ 9863 days 8 hours ago
| @ 39 days 17 hours 32 mins 1 sec
| @ 39 days 17 hours 32 mins 1.00 secs
| @ 39 days 17 hours 32 mins 2.00 secs
--- 631,638 ----
SELECT '' AS "53", d1 - timestamp '1997-01-02' AS diff
FROM TIMESTAMP_TBL WHERE d1 BETWEEN '1902-01-01' AND '2038-01-01';
53 | diff
! ----+--------------------------------------------
! | @ -9863 days -8 hours ago
| @ 39 days 17 hours 32 mins 1 sec
| @ 39 days 17 hours 32 mins 1.00 secs
| @ 39 days 17 hours 32 mins 2.00 secs

Is this now the intended behavior?

regards, tom lane