timestamptz test failed by postgresql 6.5.0

Recently, I compile the Postgresql 9.6.0 on Linux by myself. However, I meet one problem about the timestamptz.sql test case.
The expected timestamptz.out is different from the result of timestamptz.out for ime zone America/Caracas and
America/Santiago

Part of expected timestamptz.out :
DROP TABLE TIMESTAMPTZ_TST;
-- test timestamptz constructors
set TimeZone to 'America/Santiago';
-- numeric timezone
SELECT make_timestamptz(1973, 07, 15, 08, 15, 55.33);
make_timestamptz
---------------------------------
Sun Jul 15 08:15:55.33 1973 CLT
(1 row)

SELECT make_timestamptz(1973, 07, 15, 08, 15, 55.33, '+2');
make_timestamptz
---------------------------------
Sun Jul 15 02:15:55.33 1973 CLT

Part of the result timestamptz.out :
DROP TABLE TIMESTAMPTZ_TST;
-- test timestamptz constructors
set TimeZone to 'America/Santiago';
-- numeric timezone
SELECT make_timestamptz(1973, 07, 15, 08, 15, 55.33);
make_timestamptz
---------------------------------
Sun Jul 15 08:15:55.33 1973 -04
(1 row)

SELECT make_timestamptz(1973, 07, 15, 08, 15, 55.33, '+2');
make_timestamptz
---------------------------------
Sun Jul 15 02:15:55.33 1973 -04

I don't why the timezone in the output "CLT" becomes "-04" in the output. Could anyone please give me some idea to find the trouble cause?
Thanks!

Best Regards!
Tao