Add shim for querying by menu_order for <= version 3.4.

(cherry picked from commit a08bbae)

Author: nacin

mu-plugins/wordpress-shims.php

@@ -0,0 +1,15 @@
+<?php
+/*
+ * Plugin Name: WordPress Shims
+ * Author: Nacin
+ */
+
+// Add menu_order query variable for pre-3.5.
+if ( version_compare( $wp_version, '3.5-alpha', '<' ) ) :
+	add_filter( 'posts_where_paged', function( $where, $query ) {
+		global $wpdb;
+		if ( $menu_order = absint( $query->get( 'menu_order' ) ) )
+			$where .= " AND $wpdb->posts.menu_order = " . $menu_order;
+		return $where;
+	}, 10, 2 );
+endif;