在 iOS9 中现在找不到 libz.dylib 了，替换的是 libz.tbd,如果要用到 libz.dylib，可以用下面的办法，来自 Stack Overflow。
- Go to Build Phases >Link Binary with Librairies > + > Add other
- Once in the file selection window do “CMD”+Shift+G (Go to folder) and type /usr/lib/
- From /user/lib you can add : libz.dylib and more…
- Compile and have fun