What steps will reproduce the problem?
1. Execute the following code:
{{{
$db = PDB::connect($dsn, $user, $pass);
$db->setFetchMode(PDO::FETCH_CLASS, 'stdClass');
}}}

What is the expected output? What do you see instead?
Dies with:
{{{
Fatal error: Call to undefined function UnexpectedArgumentException() in
PDB/Common.php on line 509
}}}

This is because line 590 has `throw UnexpectedArgumentException` rather
than `throw new UnexpectedArgumentException`.