const golang.org/x/sys/unix.IEXTEN

2 uses

	golang.org/x/sys/unix (current package)
		zerrors_darwin_arm64.go#L541: 	IEXTEN                            = 0x400

	src.elv.sh/pkg/sys
		termios.go#L53: 	setFlag(&term.Lflag, unix.IEXTEN, v)