I've just finished to make Google Prettify support all the reserved keywords of PHP. Since Prettify already supports PHP, I had to create a new language handler called prepro so that its corresponding CSS class will be lang-prepro. Here's an example:
require_once('file.php') or die('Boo');
$test = 'Foo';
include(__FILE__);
echo $test;
You can download lang-prepro.js here.