[master] better DDNS in DLZ; mysqldyn 3821. [contrib] Added a new "mysqldyn" DLZ module with dynamic update and transaction support. Thanks to Marty Lee for the contribution. [RT #35656] 3820. [func] The DLZ API doesn't pass the database version to the lookup() function; this can cause DLZ modules that allow dynamic updates to mishandle prerequisite checks. This has been corrected by adding a 'dbversion' field to the dns_clientinfo_t structure. [RT #35656]