Postgres will turn on transaction support if explicitly turned off

class DatabaseConnection_pgsql extends DatabaseConnection {

  public function __construct(array $connection_options = array()) {
    // This driver defaults to transaction support, except if explicitly passed FALSE.
    $this->transactionSupport = !isset($connection_options['transactions']) || $connection_options['transactions'] === FALSE;

    // Default to TCP connection on port 5432.
    if (empty($connection_options['port'])) {
      $connection_options['port'] = 5432;
    }

    $dsn = 'pgsql:host=' . $connection_options['host'] . ' dbname=' . $connection_options['database'] . ' port=' . $connection_options['port'];
    parent::__construct($dsn, $connection_options['username'], $connection_options['password'], array(
      // Convert numeric values to strings when fetching.
      PDO::ATTR_STRINGIFY_FETCHES => TRUE,
      // Force column names to lower case.
      PDO::ATTR_CASE => PDO::CASE_LOWER,
    ));
  }

This says that if $connection_options['transactions'] is set and set to FALSE, then transaction support will be enabled. DamZ tells me this is a simple typo created at 3am in the morning. So not a big code change but an important one never the less.