http://php.net/manual/en/ini.core.php Cita: short_open_tag boolean
... Tells whether the short form (<? ?> ) of PHP's open tag should be allowed....
... Also if disabled, you must use the long form of the PHP open tag (<?php ?> )....
Note: This directive also affects the shorthand <?= , which is identical to <? echo . Use of this shortcut requires short_open_tag to be on.
Saludos
PD: que post tan largo para una pregunta que originalmente era tan simple jaja ^^