Pass SIGTSTP and SIGCONT signal to child.
Revoke init_tty_attribute(), and don't initialize PTY by myself.
Add workaround for gdb-io-interrupt Ctrl-C problem.
Add flag for pty-hold mode, and stop using argv[0] for flag.
Add zero-clear operation for sigaction structure.
Add workaround for cygwin's EOF detection behavior.
Set control tty on main process.
Fetch tty name from fakecygpty main process instead of subprocess.
Rewrite process-status's return value.
Modify coding style.
Change function order.