Description:
------------
Whenever I use pg_copy_to() on PostgreSQL 8.4.2 I get a warning in /var/lib/pgsql/data/postmaster.log:

> WARNING:  nonstandard use of \\ in a string literal at character 62
> HINT:  Use the escape string syntax for backslashes, e.g., E'\\'.

This is caused by the SQL generated in pg_copy_to.

r277069 addressed this issue for pg_copy_from and should also be applied to pg_copy_to.

Test script:
---------------
// setup
pg_query($db, 'CREATE TEMP TABLE temp_test_table (a INT)');
pg_query($db, 'INSERT INTO temp_test_table VALUES (1)');

// test
$rows = pg_copy_to($db, 'temp_test_table');