all: Add filesystem notification support

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/3986

vendor/github.com/zillode/notify/debug.go

@@ -0,0 +1,11 @@
+// Copyright (c) 2014-2015 The Notify Authors. All rights reserved.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+// +build !debug
+
+package notify
+
+func dbgprint(...interface{}) {}
+
+func dbgprintf(string, ...interface{}) {}