clang: error: SDK does not contain 'libarclite' at the path '/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/arc/libarclite_iphonesimulator.a'; try increasing the minimum deployment target
拷贝整个 arc 目录到新Xcode对应目录下
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/
