all: gofmt with Go 1.17

This adds "//go:build" lines and tidies up existing "// +build" lines.

Signed-off-by: Josh Bleecher Snyder <josh@tailscale.com>

net/dns/debian_resolvconf.go

@@ -2,6 +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 || freebsd || openbsd
 // +build linux freebsd openbsd
 
 package dns

net/dns/ini.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build windows
 // +build windows
 
 package dns

net/dns/ini_test.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build windows
 // +build windows
 
 package dns

net/dns/manager_default.go

@@ -2,6 +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 && !freebsd && !openbsd && !windows
 // +build !linux,!freebsd,!openbsd,!windows
 
 package dns

net/dns/nm.go

@@ -2,6 +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
 
 package dns

net/dns/openresolv.go

@@ -2,6 +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 || freebsd || openbsd
 // +build linux freebsd openbsd
 
 package dns

net/dns/resolvconf.go

@@ -2,6 +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 || freebsd || openbsd
 // +build linux freebsd openbsd
 
 package dns

net/dns/resolved.go

@@ -2,6 +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
 
 package dns

net/dns/resolver/macios_ext.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build (darwin && ts_macext) || (ios && ts_macext)
 // +build darwin,ts_macext ios,ts_macext
 
 package resolver

net/dns/resolver/neterr_other.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build !darwin && !windows
 // +build !darwin,!windows
 
 package resolver

net/dnsfallback/update-dns-fallbacks.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build ignore
 // +build ignore
 
 package main

net/interfaces/interfaces_default_route_test.go

@@ -2,6 +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 || (darwin && !ts_macext)
 // +build linux darwin,!ts_macext
 
 package interfaces

net/interfaces/interfaces_defaultrouteif_todo.go

@@ -2,6 +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 && !windows && !darwin
 // +build !linux,!windows,!darwin
 
 package interfaces

net/netns/netns_android.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build android
 // +build android
 
 package netns

net/netns/netns_darwin_tailscaled.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build darwin && !ts_macext
 // +build darwin,!ts_macext
 
 package netns

net/netns/netns_default.go

@@ -2,6 +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 && !windows && !darwin) || (darwin && ts_macext)
 // +build !linux,!windows,!darwin darwin,ts_macext
 
 package netns

net/netns/netns_linux.go

@@ -2,6 +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 && !android
 // +build linux,!android
 
 package netns

net/netns/netns_macios.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build darwin || ios
 // +build darwin ios
 
 package netns

net/netns/socks.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build !ios
 // +build !ios
 
 package netns

net/netstat/netstat_noimpl.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build !windows
 // +build !windows
 
 package netstat

net/portmapper/disabled_stubs.go

@@ -2,7 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build ios
 // +build ios
+
 // (https://github.com/tailscale/tailscale/issues/2495)
 
 package portmapper

net/portmapper/upnp.go

@@ -2,7 +2,9 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build !ios
 // +build !ios
+
 // (https://github.com/tailscale/tailscale/issues/2495)
 
 package portmapper

net/stun/stun_fuzzer.go

@@ -1,6 +1,7 @@
 // Copyright (c) 2021 Tailscale Inc & AUTHORS All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
+//go:build gofuzz
 // +build gofuzz
 
 package stun

net/tshttpproxy/tshttpproxy_future.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build tailscale_go
 // +build tailscale_go
 
 // We want to use https://github.com/golang/go/issues/41048 but it's only in the

net/tstun/ifstatus_noop.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build !windows
 // +build !windows
 
 package tstun

net/tstun/tap_unsupported.go

@@ -2,6 +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
 
 package tstun

net/tstun/tun_notwindows.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build !windows
 // +build !windows
 
 package tstun