Remove 3rd and 4th clauses in christos' license. OK christos.

fix WARNS=4 issues (const & type mismatches)

ANSI KNF

branches: 1.4.20;
- use getnameinfo instead of gethostbyaddr
- add tsa2sa and use it

find_user() in process.c does an unbounded copy into a destination
buffer that is smaller in size than the source buffer.

also, there is no guarantee that any of the string components of
the request packet are null terminated.

in some cases, not all elements of the response buffer are
explicitly set. specifically pad and addr. a talk client can spy to
see which host is talking to which host by sending out regular
packets, to which talkd responds without clearing the addr element.

from xs@kittenz.org

branches: 1.2.10; 1.2.12;
- clean up some more cruft
- support "talkd -l" for extra (syslog(3)) logging
- fix error in previous announce.c change
- use getopt
- add (missing) -d and -l descriptions to man page

- use ttymsg from libutil
- clean warnings
- PR/3778: Eric Fischer: talkd should find the least idle terminal