Properly clear the O_NONBLOCK flag after opening the TTY.
Properly clear the O_NONBLOCK flag after opening the TTY.

Though we should open the TTY with O_NONBLOCK to prevent rc(8) execution
from potentially stalling, we must not forget to clear the flag later
on, to prevent read(2) calls from failing later on.

This prevented the shell pathname prompt from working properly.

Reported by:	kib

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase