Undefined symbols for architecture i386: in libavcodec.a(pngdec.o)

Hi i have this problem in xcode..

Undefined symbols for architecture i386:
      "_inflateInit_", referenced from:
          _decode_frame in libavcodec.a(pngdec.o)
      "_inflateEnd", referenced from:
          _decode_frame in libavco开发者_Python百科dec.a(pngdec.o)
      "_inflate", referenced from:
          _decode_frame in libavcodec.a(pngdec.o)
    ld: symbol(s) not found for architecture i386
    collect2: ld returned 1 exit status

online i haven't found any solution, have any idea? thanks

From the Apple mailnglists:

To use the routines, include zlib.h in your source and libz.dylib into your project.

Or get zlib: zlib.net

Or get the CocoaPod: objective-zip