googlecart.php has a hard-coded require_once() which expects the googlerequest.php file to be 
in a directory named "library", which breaks on projects which use a different directory structure 
(e.g. includes/googlecheckout/ for us). 

The patch below removes this entirely on the grounds that the user should simply include that 
file as they do all of the other files but it might be considered preferable to do something like 
require_once(dirname(__FILE__) . "/googlerequest.php").

--- includes/GoogleCheckout/googlecart.php	(revision 45)
+++ includes/GoogleCheckout/googlecart.php	(working copy)
@@ -962,8 +962,6 @@
      *               and the redirect url returned by the server in index 1
      */
     function CheckoutServer2Server($proxy=array(), $certPath='') {
-      ini_set('include_path', ini_get('include_path').PATH_SEPARATOR.'.');
-      require_once('library/googlerequest.php');
       $GRequest = new GoogleRequest($this->merchant_id, 
                       $this->merchant_key, 
                       $this->server_url=="https://checkout.google.com/"?