Stop relying on lastError directly

Reading this directly will become deprecated in libxml2 2.14.

Author: nielsdos

ext/xml/compat.c

@@ -564,10 +564,14 @@ XML_SetEndNamespaceDeclHandler(XML_Parser parser, XML_EndNamespaceDeclHandler en
 PHP_XML_API int
 XML_Parse(XML_Parser parser, const XML_Char *data, int data_len, int is_final)
 {
-	int error;
+	int error = xmlParseChunk(parser->parser, (char *) data, data_len, is_final);
 
-	error = xmlParseChunk(parser->parser, (char *) data, data_len, is_final);
-	return !error && parser->parser->lastError.level <= XML_ERR_WARNING;
+	if (!error) {
+		const xmlError *error_data = xmlCtxtGetLastError(parser->parser);
+		return !error_data || error_data->level <= XML_ERR_WARNING;
+	}
+
+	return 0;
 }
 
 PHP_XML_API int