ssh/terminal: add support for zos Fixes golang/go#42496 Change-Id: Iae2ddb916904d9b3947bec9638c9fbf892df7b7c Reviewed-on: https://go-review.googlesource.com/c/crypto/+/269177 Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com> Trust: Tobias Klauser <tobias.klauser@gmail.com> Trust: Michael Munday <mike.munday@ibm.com> Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com> TryBot-Result: Go Bot <gobot@golang.org>