ioctl's that flush typeahead on SunOS 4.0.3

[Guy Harris]

 >As far as I can determine, the flushing of input that, contrary to
 >documentation, happened when TIOCSETN changed to/from CBREAK mode in 4.0.3,
 >is indeed fixed in 4.1, i.e. input does *not* get flushed. I have not tested
 >what happens when using the termio interface, though.

TIOCSETN uses the "termio" interface (read TTCOMPAT(4M)).