vendor: update github.com/rjeczalik/notify for go1.10 (#15785)

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

@@ -2,10 +2,52 @@
 // 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{}) {}
+import (
+	"log"
+	"os"
+	"runtime"
+	"strings"
+)
 
-func dbgprintf(string, ...interface{}) {}
+var dbgprint func(...interface{})
+
+var dbgprintf func(string, ...interface{})
+
+var dbgcallstack func(max int) []string
+
+func init() {
+	if _, ok := os.LookupEnv("NOTIFY_DEBUG"); ok || debugTag {
+		log.SetOutput(os.Stdout)
+		log.SetFlags(log.Ldate | log.Ltime | log.Lmicroseconds)
+		dbgprint = func(v ...interface{}) {
+			v = append([]interface{}{"[D] "}, v...)
+			log.Println(v...)
+		}
+		dbgprintf = func(format string, v ...interface{}) {
+			format = "[D] " + format
+			log.Printf(format, v...)
+		}
+		dbgcallstack = func(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
+		}
+		return
+	}
+	dbgprint = func(v ...interface{}) {}
+	dbgprintf = func(format string, v ...interface{}) {}
+	dbgcallstack = func(max int) []string { return nil }
+}