all: Add filesystem notification support

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

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

@@ -0,0 +1,43 @@
+// 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
+
+import (
+	"fmt"
+	"os"
+	"runtime"
+	"strings"
+)
+
+func dbgprint(v ...interface{}) {
+	fmt.Printf("[D] ")
+	fmt.Print(v...)
+	fmt.Printf("\n\n")
+}
+
+func dbgprintf(format string, v ...interface{}) {
+	fmt.Printf("[D] ")
+	fmt.Printf(format, v...)
+	fmt.Printf("\n\n")
+}
+
+func dbgcallstack(max int) []string {
+	pc, stack := make([]uintptr, max), make([]string, 0, max)
+	runtime.Callers(2, pc)
+	for _, pc := range pc {
+		if f := runtime.FuncForPC(pc); f != nil {
+			fname := f.Name()
+			idx := strings.LastIndex(fname, string(os.PathSeparator))
+			if idx != -1 {
+				stack = append(stack, fname[idx+1:])
+			} else {
+				stack = append(stack, fname)
+			}
+		}
+	}
+	return stack
+}