Add ODBC support for the new 'dsn' config value
diff --git a/system/database/drivers/odbc/odbc_driver.php b/system/database/drivers/odbc/odbc_driver.php
index 901787f..ad77311 100644
--- a/system/database/drivers/odbc/odbc_driver.php
+++ b/system/database/drivers/odbc/odbc_driver.php
@@ -57,12 +57,17 @@
 	protected $_count_string = 'SELECT COUNT(*) AS ';
 	protected $_random_keyword;
 
-
 	public function __construct($params)
 	{
 		parent::__construct($params);
 
 		$this->_random_keyword = ' RND('.time().')'; // database specific random keyword
+
+		// Legacy support for DSN in the hostname field
+		if ($this->dsn == '')
+		{
+			$this->dsn = $this->hostname;
+		}
 	}
 
 	/**
@@ -72,7 +77,7 @@
 	 */
 	public function db_connect()
 	{
-		return @odbc_connect($this->hostname, $this->username, $this->password);
+		return @odbc_connect($this->dsn, $this->username, $this->password);
 	}
 
 	// --------------------------------------------------------------------
@@ -84,7 +89,7 @@
 	 */
 	public function db_pconnect()
 	{
-		return @odbc_pconnect($this->hostname, $this->username, $this->password);
+		return @odbc_pconnect($this->dsn, $this->username, $this->password);
 	}
 
 	// --------------------------------------------------------------------