Definitaion of 'utsname' must be imported from module 'Darwin.POSIX.sys.utsname' before it is required

Definitaion of 'utsname' must be imported from module 'Darwin.POSIX.sys.utsname' before it is required

https://stackoverflow.com/questions/34430354/objective-c-gettimeofday-must-be-imported
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原文地址：https://www.cnblogs.com/royi123/p/7155335.html