Because the WP_ADMIN constant name can be bound in multiple files, all instances should check ! defined first. wp-admin/admin.php already has this check.

See #27881.


git-svn-id: https://develop.svn.wordpress.org/trunk@28478 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/admin-post.php

@@ -9,7 +9,9 @@
  */
 
 /** We are located in WordPress Administration Screens */
-define('WP_ADMIN', true);
+if ( ! defined( 'WP_ADMIN' ) ) {
+	define( 'WP_ADMIN', true );
+}
 
 if ( defined('ABSPATH') )
 	require_once(ABSPATH . 'wp-load.php');