Add signal-safe r/w function - safe_write/safe_read
Add SIGWINCH handling.
Add usage output when argc < 2.
Call exec without fork when invoked on tty.
Remove tcsetattr for piped fd.
Refine error message format.
Change termios setup values for pty master fd.
It's from child_setup_tty() in emacs/src/sysdep.c.
Merge branch 'tty-optimize' into sigwinch-support
Add sighelper for sending signal with sigval.
Add window resizing feature in fakecygpty.
Add window resizing feature.
Add signal pass through handler.
Fix some system call's EINTR guarding.
Change signal register method (introduced sigtrap_desc type).
Remove unnecessary child-process kill.
Remove sighelper's interactive mode.
Trap SIGQUIT.