TIOCPKT mode of PTY is broken if ONLCR bit is cleared.

TIOCPKT mode of PTY is broken if ONLCR bit is cleared.

	* tty.h (class tty_min): Remove variable "write_error" to which any
	errors are not currently set at anywhere.
	(class tty): Add variable "column" for handling ONOCR.
	* tty.cc (tty::init): Add initialization code for variable "column".
	* fhandler.h (class fhandler_pty_master): Remove variable "need_nl"
	which is not necessary any more. "need_nl" was needed by OPOST process
	in fhandler_pty_master::process_slave_output().
	(class fhandler_pty_common): Add function process_opost_output() for
	handling post processing for OPOST in write process.
	* fhandler_tty.cc (fhandler_pty_master::process_slave_output): Count
	TIOCPKT control byte into length to be read in TIOCPKT mode. Move
	post processing for OPOST to write process. Remove code related to
	variable "write_error". Return with EIO error if slave is already
	closed.
	(fhandler_pty_master::fhandler_pty_master): Remove initialization
	code for variable "need_nl".
	(fhandler_pty_common::process_opost_output): Add this function for
	handling of OPOST in write process. Add code to avoid blocking in
	non-blocking mode when output is suspended by ^S.
	(fhandler_pty_slave::write): Call fhandler_pty_common::
	process_opost_output() instead of WriteFile(). Remove code related to
	variable "write_error".
	(fhandler_pty_master::doecho): Call fhandler_pty_common::
	 process_opost_output() instead of WriteFile().
	* select.cc (peek_pipe): Remove code related to variable "need_nl".

Signed-off-by: Corinna Vinschen <corinna@vinschen.de>