O_NONBLOCK on stdin left set by child (using ash shell)

[Cathey, Jim]

>It seems to me that it would be bad design to have such an intent.
>IOW, one app is changing the *parent shell* in order to pass a
>non-standard state on to the next app.

Things like stty(1) do this all the time.  Seems to me that
it is up to any given program (such as a shell) to force I/O
mode bits into any states that are required for it to work
correctly, and they generally do this while leaving the rest
of the bits alone (inherited).  Not sure how this (ancient)
practice bears on the current problem.

-- Jim