The file couldn't be opened because you don't have permission to view it

下载示例代码，遇到如此错误 

The file “Graphics” couldn’t be opened because you don’t have permission to view it.

You don’t have permission.

解决方法 ：在Buildsetting中，将Compiler for C/C++/Objective-C 改为default， 重新运行就OK了！