protected static function _xcache()
{
if (static::_isHhvm()) {
throw new RuntimeException("`xcache` cannot be used with HHVM.");
}
static::_build(array('url' => 'http://xcache.lighttpd.net/pub/Releases/3.2.0/xcache-3.2.0.tar.gz', 'configure' => array('--enable-xcache')));
static::_ini(array('extension=xcache.so', 'xcache.cacher=false', 'xcache.admin.enable_auth=0', 'xcache.var_size=1M'));
}