tp_control_hdr obsoleted by cmsghdr in socket.h

my macros didn't work, make the code agree with the comments

NIST claims that no user data implies always accept; emit void control header.

mitre decbit changes

fixes to tracing and avoiding silly window between
socket layer and transport; more changes to come to usrreq and tp_send.

checkpoint for ``alpha tape''; tp is still a little broken.

Checkpoint as of first successful tp connection, before posix, &
before mckusick starts incorporating gnodes

date and time created 88/12/14 15:30:01 by sklower