1.ld: -pie can only be used when targeting iOS 4.2 or later
clang: error: linker command failed with exit code 1 (use -v to see invocation)
解决方法：点击工程project-》build setting --》搜索IPHONEOS_DEPLOYMENT_TARGET 修改为改为8.1即可
原文：http://www.cnblogs.com/dcy123/p/4929578.html