Call to undefined function check_plain in in xmlrpc.inc in drupal 4.5.5

I'm getting an error in my hourly cron run:

Fatal error: Call to undefined function: check_plain() in /home/wadsworth/www/jeaun.com/includes/xmlrpc.inc on line 67

It appears that the new version of xmlrpc.inc in drupal 4.5.5 contains a call to the check_plain function, which I believe only exists in drupal 4.6. I'm guessing that those function calls should be changed to drupal_specialchars, since the two functions appear to be doing essentially the same thing.

I've attached a patch that switches the function calls.

I can't seem to upload the patch (although it's easy enough to make manually,) so here it is:

67c67
<       return '<string>'. check_plain($xmlrpc_value->data) .'</string>';
---
>       return '<string>'. drupal_specialchars($xmlrpc_value->data) .'</string>';
80c80
<         $return .= "  <member><name>". check_plain($name) ."</name><value>";
---
>         $return .= "  <member><name>". drupal_specialchars($name) ."</name><value>";