Using LIBXML_NOERROR. Seems to be necessary for newer PHP versions
because the at sign does not suppress warnings. In a FreshRSS-specific
SimplePie section.
Warning: DOMDocument::loadXML(): Namespace prefix media on content is
not defined in Entity, line: 42 in
/..../FreshRSS/lib/SimplePie/SimplePie/Parser.php on line 144