--- ../drupal-5.0-rc2/includes/module.inc	Thu Dec  7 12:03:34 2006
+++ module.inc	Thu Jan 11 21:41:55 2007
@@ -320,7 +320,11 @@
  *   implemented in that module.
  */
 function module_hook($module, $hook) {
-  return function_exists($module .'_'. $hook);
+  static $hooklist = array();
+  if(!isset($hooklist[$module][$hook])) {
+    $hooklist[$module][$hook] = function_exists($module .'_'. $hook);
+  } 
+  return $hooklist[$module][$hook];
 }
 
 /**