php_pdo_mysql extension must be enabled for PDOConnector to work

[kinglozzer]

In order to use PDOConnector you must enable the php_pdo_mysql extension - even if you’re not using a MySQL database:

silverstripe-framework/src/ORM/Connect/PDOConnector.php

Lines 179 to 181 in db610aa

	$options = array(
	PDO::MYSQL_ATTR_INIT_COMMAND => 'SET NAMES ' . $charset . ' COLLATE ' . $connCollation
	);

If the extension isn’t enabled, PDO::MYSQL_ATTR_INIT_COMMAND isn’t defined.

Simplest fix is probably to wrap that in an if (defined('PDO::MYSQL_ATTR_INIT_COMMAND')), but a much nicer fix would be to implement @tractorcow’s suggestion here: tractorcow#18

[tractorcow]

Ah right, yes I think we should do that too. Quick fix is the defined() conditional though.