Undefined symbols for architecture i386:
  "_compressBound", referenced from:
      +[NSDataGZipAdditions compressedDataWithBytes:length:] in NSDataGZipAdditions.o
  "_compress", referenced from:
      +[NSDataGZipAdditions compressedDataWithBytes:length:] in NSDataGZipAdditions.o
  "_inflateInit_", referenced from:
      +[NSDataGZipAdditions dataWithCompressedBytes:length:] in NSDataGZipAdditions.o
  "_inflate", referenced from:
      +[NSDataGZipAdditions dataWithCompressedBytes:length:] in NSDataGZipAdditions.o
      -[ParserForMainReturn uncompressZippedData:] in ParserForMainReturn.o
  "_inflateEnd", referenced from:
      +[NSDataGZipAdditions dataWithCompressedBytes:length:] in NSDataGZipAdditions.o
      -[ParserForMainReturn uncompressZippedData:] in ParserForMainReturn.o
  "_inflateInit2_", referenced from:
      -[ParserForMainReturn uncompressZippedData:] in ParserForMainReturn.o
ld: symbol(s) not found for architecture i386
clang: error: linker command failed with exit code 1 (use -v to see invocation)

如果老是出现上面的错误。那么在工程中加入libz.dlib 文件就妥妥的了。