如果有用到libz.1.2.3.dylib這個framework（例如ASIHTTP）
iOS SDK升級到5 beta會遇到下列錯誤：
ld: library not found for -lz.1.2.3
collect2: ld returned 1 exit status
Command /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/llvm-g++-4.2 failed with exit code 1
或是用了ASIHTTP：
