BUG #2535: Unicode on Windows: aogonek is not distinguished from agrave

The following bug has been logged online:

Bug reference:      2535
Logged by:          Marius Žalinauskas
Email address:      mariusz@splius.lt
PostgreSQL version: 8.1.4
Operating system:   Windows XP Pro
Description:        Unicode on Windows: aogonek is not distinguished from
agrave
Details:

It seems that on Windows PostgreSQL v8.1.4 does not distinguish aogonek
(U+0104, U+0105) from agrave (U+00C0, U+00E0):

CREATE DATABASE tests ENCODING = 'UTF8';

\c tests

CREATE TABLE foo
(
  bar char(1) PRIMARY KEY
);

-- OK
INSERT INTO foo (bar) VALUES ('ą');

-- ERROR: duplicate key violates unique constraint
INSERT INTO foo (bar) VALUES ('à');

-- Same thing with capitals

-- OK
INSERT INTO foo (bar) VALUES ('Ą');

-- ERROR: duplicate key violates unique constraint
INSERT INTO foo (bar) VALUES ('À');