The new RIP implementation fixes plenty of old bugs and also adds support
for many new features: ECMP support, link state support, BFD support,
configurable split horizon and more. Most options are now per-interface.
(the current version UNIX-specific) anyway, so it's useless to try splitting it
to sysdep and generic part. Instead of this, configure script decides (based on
system type and user's wish) what (if any) client should be built and what
autoconfiguration it requires. Also, the client provides its own die/bug/...
functions.