locale changes

 In the atache is patch with this:

 SET LOCALE TO <value>
        Set locale to <value>, the <value> must be correct for
        current OS locale setting.

 SHOW LOCALE
        Show current locale setting for all categories.

 RESET LOCALE
        Set locale back to start-up setting.

 Now, possible is change locale environment from client without backend
restart and under one postmaster can run more backends with different
locale setting.

 All routines (formatting.c, cash.c, main.c) are correct for this change.

 BTW. --- how plan is 'money' datetype in 7.1, remove?

                     Karel

 An example:

test=# SHOW LOCALE;
NOTICE:  Locale setting: LANG=C, CTYPE=C, NUMERIC=C, TIME=C, COLLATE=C,
MONETARY=C, MESSAGES=C
SHOW VARIABLE
test=# SELECT to_char(1023.5, 'L 9999D9');
  to_char
-----------
    1023.5
(1 row)

test=# SET LOCALE TO 'de_DE';
SET VARIABLE
test=# SELECT to_char(1023.5, 'L 9999D9');
  to_char
------------
 DM  1023,5
(1 row)

test=# SET LOCALE TO 'en_US';
SET VARIABLE
test=# SELECT to_char(1023.5, 'L 9999D9');
  to_char
-----------
 $  1023.5
(1 row)

test=# RESET LOCALE;
RESET VARIABLE
test=# SELECT to_char(1023.5, 'L 9999D9');
  to_char
-----------
    1023.5
(1 row)