我编写了一个使用 Google Identity Toolkit 登录的应用程序，它运行良好，直到我更新到最新版本的 Xcode 并开始为 iOS 9 开发。我不得不使用 Cocoapods 安装 GITkit，这似乎已经成功，但现在在编译时，当我引用某些内置类时出现以下错误。此外，我不得不将我的导入语句从 更改#import <GITkit/GITkit.h>为#import "GITkit.h"。
Undefined symbols for architecture x86_64:
"_OBJC_CLASS_$_GITClient", referenced from:
objc-class-ref in H2LoginViewController.o
objc-class-ref in H2AppDelegate.o
"_OBJC_CLASS_$_GITIDToken", referenced from:
objc-class-ref in H2LoginViewController.o
"_OBJC_CLASS_$_GITInterfaceManager", referenced from:
objc-class-ref in H2LoginViewController.o
"_kGITProviderFacebook", referenced from:
-[H2AppDelegate application:didFinishLaunchingWithOptions:] in H2AppDelegate.o
"_kGITProviderGoogle", referenced from:
-[H2AppDelegate application:didFinishLaunchingWithOptions:] in H2AppDelegate.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
任何帮助将不胜感激。谢谢。