patch to fix non-echo tty on scp SIGINT

[Damien Miller]

Darren Tucker wrote:

> (Incidentally, on Linux, strace isn't ideal for debugging this kind of 
> parent-child interaction since strace will change the behaviour of the 
> processes slightly.  Don't ask how long it took to figure that out... )

Worse, attaching and detaching strace to some processes will tickle
things so that system calls may be interrupted - so tracing a
long-running program to see what has happened can cause it to die.

I also found this out the hard way...

-d