🚀 go-pugleaf

I hope emacs is not changed to include that code.  The
conditionalizations are too dependant upon specific systems!

For example, I have a system V which is neither of the two exceptions
given (RTU and UNIPLUS) but does support bsd style setpgrp(x,y) and
TIOC[SP]GRP (but unfortunately not yet SIGSTOP, SIGCONT and friends). 

Chances are, if a Sys5 lacks TIOCSPGRP, it also lacks a bad-style
setpgrp() and vice versa.  Thus TIOCSPGRP would be a good candidate
for the conditionalization.

Btw, on a separate but related topic, the code for flushing input
under SYS5 should really (!!!) use TCFLSH and not TCSETAW, which
results in erroneous display behavior on pty's used by a full rlogin
protocol.  (I sent rms mail on this a while back, so hopefully a fix
will appear in v19).