lib/connections: Try TCP punchthrough (fixes #4259) (#5753)

lib/dialer/control_unsupported.go

@@ -0,0 +1,17 @@
+// Copyright (C) 2019 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+// +build solaris
+
+package dialer
+
+import "syscall"
+
+var SupportsReusePort = false
+
+func ReusePortControl(_, _ string, _ syscall.RawConn) error {
+	return nil
+}