Description:
------------
When calling xmlrpc_decode_request with invalid XML data, the following error is output to STDERR:

expat reports error code 4
        description: Empty document
        line: 1
        column: 1
        byte index: 0
        total bytes: 0

        data beginning 0 before byte index: dfsdffsd

There seems to be no way to turn it off: I want to be able to handler the error myself, and do not want the error message cluttering the output needlessly.

Reproduce code:
---------------
<?php
x = '';
o = xmlrpc_decode_request('dfsdffsd', $x);
?>


Expected result:
----------------
For there to be some way to turn this error message off, or have it redirected to a variable or accessible via some library call.

Actual result:
--------------
expat reports error code 4
        description: Empty document
        line: 1
        column: 1
        byte index: 0
        total bytes: 0

        data beginning 0 before byte index: dfsdffsd