- #pragma once include guard
- include string.h to get memset and memcmp prototypes to fix respondd
  provider build warning

(cherry picked from commit e32fa5bc)

When the network connectivity is bad, routers may not appear in the
translation tables, or there may be no originator with TQ >0. Such
conditions to not warrant spamming the log with error messages.

(cherry picked from commit fcd07de6)

(cherry picked from commit e384f899)

[Matthias Schiffer: fix up start/stop order and file permissions]

Fixes: 8e5abf02 ("treewide: switch to ebtables-tiny")

This package drops all incoming router advertisements except for the
default router with the best metric according to B.A.T.M.A.N. advanced.

Note that advertisements originating from the node itself (for example
via gluon-radvd) are not affected.