[Typo3] Couldn't find the include_once statement for XCLASS!

[tapio]

> Couldn't find the include_once statement for XCLASS!

many extension have this kind of statement in the end of ext_localconf.php

// Include extension?
if (defined('TYPO3_MODE') && 
$TYPO3_CONF_VARS[TYPO3_MODE]['XCLASS']['typo3/mod/tools/em/index.php'])	{ 
include_once($TYPO3_CONF_VARS[TYPO3_MODE]['XCLASS']['typo3/mod/tools/em/index.php']);
}

It is now missig from some plugins.