wrong behavior using to_char()

Hi,

I notice a strange behavior using to_char() function. I'm using locale
pt_BR but it could happen with any locale.

template1=# select to_char(12345.67, '999G999D999');
to_char
--------------
12,345,670
(1 registro)

In the pt_BR locale, the thousand separator is "". So it should return
12345,670. Looking at the source, I saw that the test cases for locale
properties are independent among them. I think that the correct form is to
have all-or-nothing test case or didn't test *lconv->property ("" is
evaluated to false). Attached is a patch that fixes it using the second
option.

--
Euler Taveira de Oliveira
http://www.timbira.com/