ash/atty on PMAX

[Derek.Beatty at cs.cmu.edu]

On the Decstation 3100 under Ultrix Worksystem V2.0, ash compiled -O2
handles SIGINT wrongly; when compiled -g it seems fine.  Be sure to
define BSD and SYSV in shell.h.  Atty seems to work compiled with any
options, but I deleted the call to clearinput() from runtty() to make
file name completion work, and even then it prints an extra prompt.

 -- Derek Beatty
    CS graduate student, Carnegie-Mellon University