ssh: make it build on darwin

For local dev testing initially. Product-wise, it'll probably only be
workable on the two unsandboxed builds.

Updates #3802

Change-Id: Ic352f966e7fb29aff897217d79b383131bf3f92b
Signed-off-by: Brad Fitzpatrick <[email protected]>

cmd/tailscaled/depaware.txt

@@ -3,7 +3,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
    W 💣 github.com/alexbrainman/sspi                                 from github.com/alexbrainman/sspi/internal/common+
    W    github.com/alexbrainman/sspi/internal/common                 from github.com/alexbrainman/sspi/negotiate
    W 💣 github.com/alexbrainman/sspi/negotiate                       from tailscale.com/net/tshttpproxy
-   L    github.com/anmitsu/go-shlex                                  from github.com/gliderlabs/ssh
+  LD    github.com/anmitsu/go-shlex                                  from github.com/gliderlabs/ssh
    L    github.com/aws/aws-sdk-go-v2                                 from github.com/aws/aws-sdk-go-v2/internal/ini
    L    github.com/aws/aws-sdk-go-v2/aws                             from github.com/aws/aws-sdk-go-v2/aws/middleware+
    L    github.com/aws/aws-sdk-go-v2/aws/arn                         from tailscale.com/ipn/store/aws
@@ -61,8 +61,8 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
    L    github.com/aws/smithy-go/transport/http/internal/io          from github.com/aws/smithy-go/transport/http
    L    github.com/aws/smithy-go/waiter                              from github.com/aws/aws-sdk-go-v2/service/ssm
    L    github.com/coreos/go-iptables/iptables                       from tailscale.com/wgengine/router
-   L 💣 github.com/creack/pty                                        from tailscale.com/ssh/tailssh
-   L    github.com/gliderlabs/ssh                                    from tailscale.com/ssh/tailssh
+  LD 💣 github.com/creack/pty                                        from tailscale.com/ssh/tailssh
+  LD    github.com/gliderlabs/ssh                                    from tailscale.com/ssh/tailssh
    W 💣 github.com/go-ole/go-ole                                     from github.com/go-ole/go-ole/oleutil+
    W 💣 github.com/go-ole/go-ole/oleutil                             from tailscale.com/wgengine/winnet
    L 💣 github.com/godbus/dbus/v5                                    from tailscale.com/net/dns
@@ -219,7 +219,7 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         tailscale.com/portlist                                       from tailscale.com/ipn/ipnlocal
         tailscale.com/safesocket                                     from tailscale.com/client/tailscale+
         tailscale.com/smallzstd                                      from tailscale.com/ipn/ipnserver+
-   L 💣 tailscale.com/ssh/tailssh                                    from tailscale.com/wgengine/netstack
+  LD 💣 tailscale.com/ssh/tailssh                                    from tailscale.com/wgengine/netstack
      💣 tailscale.com/syncs                                          from tailscale.com/control/controlknobs+
         tailscale.com/tailcfg                                        from tailscale.com/client/tailscale+
    W    tailscale.com/tsconst                                        from tailscale.com/net/interfaces
@@ -272,19 +272,19 @@ tailscale.com/cmd/tailscaled dependencies: (generated by github.com/tailscale/de
         golang.org/x/crypto/acme                                     from tailscale.com/ipn/localapi
         golang.org/x/crypto/blake2b                                  from golang.org/x/crypto/nacl/box
         golang.org/x/crypto/blake2s                                  from golang.zx2c4.com/wireguard/device
-   L    golang.org/x/crypto/blowfish                                 from golang.org/x/crypto/ssh/internal/bcrypt_pbkdf
+  LD    golang.org/x/crypto/blowfish                                 from golang.org/x/crypto/ssh/internal/bcrypt_pbkdf
         golang.org/x/crypto/chacha20                                 from golang.org/x/crypto/chacha20poly1305+
         golang.org/x/crypto/chacha20poly1305                         from crypto/tls+
         golang.org/x/crypto/cryptobyte                               from crypto/ecdsa+
         golang.org/x/crypto/cryptobyte/asn1                          from crypto/ecdsa+
         golang.org/x/crypto/curve25519                               from crypto/tls+
-   L    golang.org/x/crypto/ed25519                                  from golang.org/x/crypto/ssh
+  LD    golang.org/x/crypto/ed25519                                  from golang.org/x/crypto/ssh
         golang.org/x/crypto/hkdf                                     from crypto/tls
         golang.org/x/crypto/nacl/box                                 from tailscale.com/types/key
         golang.org/x/crypto/nacl/secretbox                           from golang.org/x/crypto/nacl/box
         golang.org/x/crypto/poly1305                                 from golang.org/x/crypto/chacha20poly1305+
         golang.org/x/crypto/salsa20/salsa                            from golang.org/x/crypto/nacl/box+
-   L    golang.org/x/crypto/ssh                                      from github.com/gliderlabs/ssh+
+  LD    golang.org/x/crypto/ssh                                      from github.com/gliderlabs/ssh+
         golang.org/x/net/bpf                                         from github.com/mdlayher/netlink+
         golang.org/x/net/dns/dnsmessage                              from net+
         golang.org/x/net/http/httpguts                               from net/http+

ipn/ipnlocal/ssh.go

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build linux
-// +build linux
+//go:build linux || (darwin && !ios)
+// +build linux darwin,!ios
 
 package ipnlocal
 

ipn/ipnlocal/ssh_stub.go

@@ -2,8 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build !linux
-// +build !linux
+//go:build ios || (!linux && !darwin)
 
 package ipnlocal
 

ssh/tailssh/tailssh.go

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build linux
-// +build linux
+//go:build linux || (darwin && !ios)
+// +build linux darwin,!ios
 
 // Package tailssh is an SSH server integrated into Tailscale.
 package tailssh

ssh/tailssh/tailssh_test.go

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build linux
-// +build linux
+//go:build linux || darwin
+// +build linux darwin
 
 package tailssh
 

wgengine/netstack/ssh.go

@@ -2,8 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
-//go:build linux
-// +build linux
+//go:build linux || (darwin && !ios)
+// +build linux darwin,!ios
 
 package netstack