add kamirepl, a REPL to test kamid

actually parse the header

first stab at 9p in the client proc: parse 9p messages

pretty-print 9p message types

move MIN to header

avoid read out-of-bounds

first stab at 9p

include err.h if available

fix make dist

add missing source deps on kamid.h

factorize the two version of random_id

fix build for !HAVE_ARC4RANDOM

error also if `tls pki' is missing

add flags to listener; warn if missing auth_table in the future we'll have also plain 9p, so mark the tls listeners with L_TLS and add the libtls machinery only in that case.

don't bundle arc4random, if not available use incremented counter it doesn't seem to work on guix, I don't feel fine editing crypto-related code and it was only used to generate a random id for clients connection. I'd love if someone will solve this thought :)