Since PHP 4.3.0-r1 the ability to use the CGI Version of PHP is no longer available, since it was not a secure Version. But i think there should also be a CGI Version of PHP with --enable-force-cgi-redirect and --enable-discard-path. So how implent this CGI Version, with an extra ebuild or within the PHP ebuild ?
mod_php has both of those features turned on by default php does not because, well it's a cli binary