Use termios via CGO

Signed-off-by: Yohei Ueda <yohei@jp.ibm.com>
Use termios via CGO only on Linux

Signed-off-by: Yohei Ueda <yohei@jp.ibm.com>
Merge pull request #9279 from yoheiueda/termios-via-cgo

Use termios via CGO