rewrite checkpoint

vendor/github.com/AlecAivazis/survey/terminal/runereader_bsd.go

@@ -0,0 +1,13 @@
+// copied from: https://github.com/golang/crypto/blob/master/ssh/terminal/util_bsd.go
+// Copyright 2013 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// +build darwin dragonfly freebsd netbsd openbsd
+
+package terminal
+
+import "syscall"
+
+const ioctlReadTermios = syscall.TIOCGETA
+const ioctlWriteTermios = syscall.TIOCSETA