* fhandler_console.cc (fhandler_console::open): Specify second argument to
tcinit.
* fhandler_termios.cc (fhandler_termios::tcinit): Rename second argument. Set
pgid to 0 if this is a pty master.
(fhandler_termios::tcgetpgrp): Just return value of pgid. It will be zero if
not initialized.
* fhandler_tty.cc (fhandler_tty_slave::open): Specify second argument to
tcinit.
(fhandler_tty_slave::ioctl): Implement TIOCGPRP/TIOCSPGRP. Fix switch
indentation.
(fhandler_tty_master::ioctl): Implement TIOCGPRP/TIOCSPGRP.
* include/sys/termios.h (TIOCGPGRP): Define similarly to Linux.
* include/sys/termios.h (TIOCSPGRP): Ditto.