unity3d导出xcode项目使用afnetworking 3框架导致_kUTTagClassMIMEType 问题解决方案

http://blog.csdn.net/huayu_huayu/article/details/51781953 （参考链接）

Undefined symbols for architecture armv7:

"_kUTTagClassMIMEType", referenced from:

  -[AFStreamingMultipartFormData appendPartWithFileURL:name:error:] in AFURLRequestSerialization.o

"_kUTTagClassFilenameExtension", referenced from:

  -[AFStreamingMultipartFormData appendPartWithFileURL:name:error:] in AFURLRequestSerialization.o

"_UTTypeCreatePreferredIdentifierForTag", referenced from:

  -[AFStreamingMultipartFormData appendPartWithFileURL:name:error:] in AFURLRequestSerialization.o

"_UTTypeCopyPreferredTagWithClass", referenced from:

  -[AFStreamingMultipartFormData appendPartWithFileURL:name:error:] in AFURLRequestSerialization.o

ld: symbol(s) not found for architecture armv7

clang: error: linker command failed with exit code 1 (use -v to see invocation)

解决方法：

这是缺少MobileCoreServices.framework

引入MobileCoreServices.framework即可