BSD vs. SVR4 typehead flush after tty mode change

[David Elliott]

I execute the following command line:

	sleep 5 ; cat /etc/passwd | more > /dev/null

While the sleep is still running, I type "date" (followed
by RETURN) 3 times.

Under BSD, I get 3 date commands run.  Under RISC/OS on a MIPS M2000,
the same happens.  Under our SVR4 system, I get nothing -- the input
has disappeared.

Is there an stty setting that will fix this?  Is it just a difference
between the operating systems, or is it a problem with 'more' changing
the tty mode when it shouldn't?

I should also mention that similar things happen when I am getting
out of vi.  It's annoying to lose typeahead, and I generally
think a few seconds ahead of myself.  I guess I need faster
computers ;-)