buildroot

knock: new package

A port knocking implementation with daemon and user application.

[Peter: drop trailing newline in Config.in]
Signed-off-by: Michael Rommel <rommel@layer-7.net>
Acked-by: Thomas De Schampheleire <thomas.de.schampheleire@gmail.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>