Index: modules/system/system.install
===================================================================
RCS file: /cvs/drupal/drupal/modules/system/system.install,v
retrieving revision 1.316
diff -u -p -r1.316 system.install
--- modules/system/system.install	20 Apr 2009 02:23:16 -0000	1.316
+++ modules/system/system.install	26 Apr 2009 10:47:48 -0000
@@ -42,6 +42,17 @@ function system_requirements($phase) {
     $requirements['php']['severity'] = REQUIREMENT_ERROR;
   }
 
+  // Make sure the Tokenizer extension is enabled, which is required by the code registry.
+  $requirements['php_tokenizer'] = array(
+    'title' => $t('PHP Tokenizer'),
+    'value' => $t('Enabled'),
+  );
+  if (!function_exists('token_get_all')) {
+    $requirements['php_tokenizer']['value'] = $t('Not enabled');
+    $requirements['php_tokenizer']['description'] = $t('Drupal requires the <a href="@url">Tokenizer</a> PHP extension to be enabled.', array('@url' => 'http://php.net/tokenizer'));
+    $requirements['php_tokenizer']['severity'] = REQUIREMENT_ERROR;
+  }
+
   // Test PHP register_globals setting.
   $requirements['php_register_globals'] = array(
     'title' => $t('PHP register globals'),