"PR/54435: Adjust for new kernel behavior of soreceive(9) clearing MSG_OOB"
That change was trying to make rlogin work again after the SIOCATMARK ioctl
was broken, but that kernel bug has now been fixed, so the original rlogin code
now works again. Further, the changed rlogin code actually did the wrong thing,
by treating reception of the MSG_OOB byte as meaning that we are now
"at the mark", but that is not true... we are "at the mark" only when
we have reached the point in the stream where the MSG_OOB byte was originally,
as indicated by SIOCATMARK. So going back to the previous code seems best
all around. ok'd by christos.
5b182ca27f