util/systemd: don't link systemd-notification package on Android

Updates #12614

Change-Id: Ie5f0bb072571249f08aca09132c8491c31d01605
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

tsnet/depaware.txt

@@ -132,7 +132,7 @@ tailscale.com/tsnet dependencies: (generated by github.com/tailscale/depaware)
    L 💣 github.com/mdlayher/netlink                                  from github.com/google/nftables+
    L 💣 github.com/mdlayher/netlink/nlenc                            from github.com/jsimonetti/rtnetlink+
    L    github.com/mdlayher/netlink/nltest                           from github.com/google/nftables
-  LA    github.com/mdlayher/sdnotify                                 from tailscale.com/util/systemd
+   L    github.com/mdlayher/sdnotify                                 from tailscale.com/util/systemd
   LA 💣 github.com/mdlayher/socket                                   from github.com/mdlayher/netlink+
         github.com/miekg/dns                                         from tailscale.com/net/dns/recursive
  LDWA 💣 github.com/mitchellh/go-ps                                   from tailscale.com/safesocket

util/systemd/systemd_linux.go

@@ -1,7 +1,7 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
-//go:build linux
+//go:build linux && !android
 
 package systemd
 

util/systemd/systemd_nonlinux.go

@@ -1,7 +1,7 @@
 // Copyright (c) Tailscale Inc & AUTHORS
 // SPDX-License-Identifier: BSD-3-Clause
 
-//go:build !linux
+//go:build !linux || android
 
 package systemd