Index: wp-includes/user.php
===================================================================
--- wp-includes/user.php	(revision 16916)
+++ wp-includes/user.php	(working copy)
@@ -412,6 +412,8 @@
 		// sorting
 		if ( in_array( $qv['orderby'], array('email', 'url', 'registered') ) ) {
 			$orderby = 'user_' . $qv['orderby'];
+		} elseif ( in_array( $qv['orderby'], array('user_email', 'user_url', 'user_registered') ) ) {
+			$orderby = $qv['orderby'];
 		} elseif ( 'name' == $qv['orderby'] || 'display_name' == $qv['orderby'] ) {
 			$orderby = 'display_name';
 		} elseif ( 'post_count' == $qv['orderby'] ) {
Index: wp-includes/meta.php
===================================================================
--- wp-includes/meta.php	(revision 16916)
+++ wp-includes/meta.php	(working copy)
@@ -352,7 +352,7 @@
 	return $cache;
 }
 
-/*
+/**
  * Given a meta query, generates SQL clauses to be appended to a main query
  *
  * @since 3.1.0