我正在尝试Unity的firebase消息传递，我遵循https://firebase.google.com/docs/cloud-messaging/unity/client的指令，但是我在构建时会出现错误
错误1：
Error: Error while saving blame file, build will continue
Error: The prefix "tools" for attribute "tools:overrideLibrary" associated with an element type "uses-sdk" is not bound.
UnityEditor.HostView:OnGUI()
错误2：
AndroidSDKToolsException: Unable to merge android manifests. See the Console for more details.
UnityEditor.Android.AndroidSDKTools.DetectErrorsAndWarnings (System.String logMessages, System.String errorMsg)
UnityEditor.Android.AndroidSDKTools.RunCommandInternal (System.String javaExe, System.String sdkToolsDir, System.String[] sdkToolCommand, Int32 memoryMB, System.String workingdir, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
UnityEditor.Android.AndroidSDKTools.RunCommandSafe (System.String javaExe, System.String sdkToolsDir, System.String[] sdkToolCommand, Int32 memoryMB, System.String workingdir, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
UnityEditor.Android.AndroidSDKTools.RunCommand (System.String[] sdkToolCommand, Int32 memoryMB, System.String workingdir, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
UnityEditor.Android.AndroidSDKTools.RunCommand (System.String[] sdkToolCommand, System.String workingdir, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit, System.String errorMsg)
UnityEditor.Android.AndroidSDKTools.RunCommand (System.String[] sdkToolCommand, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit,System.String errorMsg)
UnityEditor.Android.AndroidSDKTools.MergeManifests (System.String target, System.String mainManifest, System.String[] libraryManifests, UnityEditor.Android.WaitingForProcessToExit waitingForProcessToExit)
UnityEditor.Android.PostProcessor.Tasks.GenerateManifest.MergeManifests (UnityEditor.Android.PostProcessor.PostProcessorContext context, System.String targetManifest, System.String mainManifest)
UnityEditor.Android.PostProcessor.Tasks.GenerateManifest.Execute (UnityEditor.Android.PostProcessor.PostProcessorContext context)
UnityEditor.Android.PostProcessor.PostProcessRunner.RunAllTasks (UnityEditor.Android.PostProcessor.PostProcessorContext context)
UnityEditor.HostView:OnGUI()
在Unity问题跟踪器上找到的解决方案：
只需打开https://developer.android.com/studio/index.html向下滚动到该页面的底部去下载向下滚动到该页面的底部查找Windows" tools_r25.2.3-windows.zip"下载并解压缩查找MacOSX" Tools_R25.2.3-Macosx.zip"下载并解压缩。在SDK路径中，替换工具文件夹。