Index: wp-includes/wp-db.php
===================================================================
--- wp-includes/wp-db.php	(revision 23175)
+++ wp-includes/wp-db.php	(working copy)
@@ -987,10 +987,13 @@
 	 * @return null|false|string Sanitized query string, null if there is no query, false if there is an error and string
 	 * 	if there was something to prepare
 	 */
-	function prepare( $query, $args ) {
+	function prepare( $query, $args = null ) {
 		if ( is_null( $query ) )
 			return;
 
+		if ( is_null( $args ) )
+			_doing_it_wrong( __METHOD__, sprintf( __( 'The %s parameter should not be empty.' ), '<code>$args</code>' ), '3.5' );
+
 		$args = func_get_args();
 		array_shift( $args );
 		// If args were passed as an array (as in vsprintf), move them up