一个奇怪的Mach-O链接器错误出现在我拥有的每个项目上，甚至是我从模板创建并且没有任何改变的项目。这是错误：
ld: warning: ignoring file /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk/System/Library/Frameworks//UIKit.framework/UIKit, missing required architecture armv7 in file /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk/System/Library/Frameworks//UIKit.framework/UIKit (1 slices)
ld: in '/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk/System/Library/Frameworks//Security.framework/Security', missing required architecture armv7 in file /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS7.0.sdk/System/Library/Frameworks//Security.framework/Security (1 slices) for architecture armv7
clang: error: linker command failed with exit code 1 (use -v to see invocation)