could not build module ‘Foundation’, could not build module ‘UIKit’……23个错误

pch文件加入

#import <Availability.h>

 

#ifndef __IPHONE_3_0

#warning "This project uses features only available in iOS SDK 3.0 and later."

#endif

 

#ifdef __OBJC__

#import <UIKit/UIKit.h>

#import <Foundation/Foundation.h>