Declare $wpdb->base_prefix.

props DavidAnderson.
fixes #16762.


git-svn-id: https://develop.svn.wordpress.org/trunk@27249 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/wp-db.php

@@ -180,6 +180,15 @@ class wpdb {
 	 */
 	var $prefix = '';
 
+	/**
+	 * WordPress base table prefix.
+	 *
+	 * @since 3.0.0
+	 * @access public
+	 * @var string
+	 */
+	 public $base_prefix;
+
 	/**
 	 * Whether the database queries are ready to start executing.
 	 *