facebook/hhvm — pull request #3621 by simonwelsh (2014-08-29 04:26:14+00:00)
Title: Implement the shell of xdebug_is_enabled

This allows for if(!function_exists('xdebug_is_enabled') || !xdebug_is_enabled()) style-checks to see if custom behaviour should be used instead of xdebug stuff.