Re: Australian timezone configure option

> Hi,
> 
> Being in Australia, it's always been a minor pain building the support
> for Australian timezone rules by defining USE_AUSTRALIAN_RULES to the
> compiler.  Not to mention the not inconsiderable pain involved in pawing
> through the code and documentation trying to work out why the timezones
> were wrong in the first place.

OK, this patch makes Australian_timezones a GUC option.  It can be set
anytime in psql.  The code uses a static variable to check if the GUC
setting has changed and adjust the C struct accordingly.  I have also
added code to allow the regression tests to pass even if postgresql.conf
has australian_timezones defined.

	test=>  select datetime('2001-01-01 00:00:00 EST');
	       timestamp        
	------------------------
	 2001-01-01 00:00:00-05
	(1 row)
	
	test=> set australian_timezones = true;
	SET VARIABLE
	test=>  select datetime('2001-01-01 00:00:00 EST');
	       timestamp        
	------------------------
	 2000-12-31 09:00:00-05
	(1 row)
	test=> reset all;
	RESET VARIABLE
	test=>  select datetime('2001-01-01 00:00:00 EST');
	       timestamp        
	------------------------
	 2001-01-01 00:00:00-05
	(1 row)

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
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