In 3.5.1, have $wpdb->prepare() issue a notice for an insufficient number of arguments, instead of a warning. see #22873.

git-svn-id: http://core.svn.wordpress.org/branches/3.5@23215 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/wp-db.php

@@ -987,10 +987,13 @@ class wpdb {
 	 * @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 ( func_num_args() < 2 )
+			_doing_it_wrong( 'wpdb::prepare', sprintf( 'wpdb::prepare() requires at least two arguments.' ), '3.5' );
+
 		$args = func_get_args();
 		array_shift( $args );
 		// If args were passed as an array (as in vsprintf), move them up