cmd/tailscale: mostly fix 'tailscale ssh' on macOS (sandbox)

Browse Source

Still a little wonky, though. See the tcsetattr error and inability to
hit Ctrl-D, for instance:

    bradfitz@laptop ~ % tailscale.app ssh foo@bar
    tcsetattr: Operation not permitted
    # Authentication checked with Tailscale SSH.
    # Time since last authentication: 1h13m22s
    foo@bar:~$ ^D
    ^D
    ^D

Updates #4518
Updates #4529

Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

...

This commit is contained in:

500 Internal Server Error

Gitea Version: 1.28.0+dev-477-g8b6ad49a5f