Introduce a special wp_die handler for XMLRPC requests to ensure we send an XML response.

Props koke for the original patch. See #16748.

git-svn-id: http://svn.automattic.com/wordpress/trunk@17643 1a063a9b-81f0-0310-95a4-ce76da25c4cd

xmlrpc.php

@@ -98,6 +98,9 @@ function logIO($io,$msg) {
 if ( isset($HTTP_RAW_POST_DATA) )
 	logIO("I", $HTTP_RAW_POST_DATA);
 
+// Make sure wp_die output is XML
+add_filter( 'wp_die_handler', '_xmlrpc_wp_die_filter' );
+
 // Allow for a plugin to insert a different class to handle requests.
 $wp_xmlrpc_server_class = apply_filters('wp_xmlrpc_server_class', 'wp_xmlrpc_server');
 $wp_xmlrpc_server = new $wp_xmlrpc_server_class;