Update

vendor/tailscale.com/feature/condlite/expvar/expvar.go

@@ -0,0 +1,12 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build !(ts_omit_debug && ts_omit_clientmetrics && ts_omit_usermetrics)
+
+// Package expvar contains type aliases for expvar types, to allow conditionally
+// excluding the package from builds.
+package expvar
+
+import "expvar"
+
+type Int = expvar.Int

vendor/tailscale.com/feature/condlite/expvar/omit.go

@@ -0,0 +1,11 @@
+// Copyright (c) Tailscale Inc & AUTHORS
+// SPDX-License-Identifier: BSD-3-Clause
+
+//go:build ts_omit_debug && ts_omit_clientmetrics && ts_omit_usermetrics
+
+// excluding the package from builds.
+package expvar
+
+type Int int64
+
+func (*Int) Add(int64) {}