PHP错误解析Realurl配置文件

I have installed the typo3 rearurl extension in Typo3. If I copy to the default manual config location typo3conf/realurl_conf.php a configuration file with for example:

<?PHP
   $TYPO3_CONF_VARS['EXTCONF']['realurl'] = array(
      '_DEFAULT' => array(

      ),
   );
?>

I getting PHP errors like below?

Parse error: syntax error, unexpected '$TYPO3_CONF_VARS' (T_VARIABLE) in /home/extension/public_html/typo3conf/realurl_conf.php on line 1

Use this instead

<?PHP
$GLOBALS['TYPO3_CONF_VARS']['EXTCONF']['realurl'] = array(
   '_DEFAULT' => array(

   ),
);
?>

In newer version there are some problems with $TYPO3_CONF_VARS vs $GLOBALS['TYPO3_CONF_VARS'] the last one works always.