I've stuck to only doing this in the places where I'm sure we should never get false back. Other places I'm less sure of (and I found more bugs along the way).
This reverts commit cbe0f44c4f7bc3715acbf148f981bd93111c4c8f.
This achieves the same result as the reverted commit wrt. process in the
same manner (writing a keepalive into the socket and checking if it
failed to send). However, it does _not_ allow the process to die on
reaching pipe EOF, since this can cause many spams of subprocesses when
stdin is actually not a tty (e.g. in a Docker container).
