title: zlib miniunzip fails to open zip files
body: <p>I installed zlib 1.2.8 and built the miniunzip and minizip projects to test creating and opening a zip.  </p>
  
  <p>I built as debug on visual studio 2010 32 bit, with the debug dll zlibwapid .</p>
  
  <p>Minizip worked fine to create a zip file however miniunzip failed to open the zipfile created, and looking in miniunz.c the failure is because:
  <code>uf = unzOpen2_64(zipfilename,&amp;ffunc);</code> returns 0.  </p>
  
  <p>I saw the code is wrapped as follows in defines:</p>
  
  <pre><code>#ifdef USEWIN32IOAPI
      fill_win32_filefunc64A(&amp;ffunc);
      uf = unzOpen2_64(zipfilename,&amp;ffunc);
  #else
       uf = unzOpen64(zipfilename);
  #endif
  </code></pre>
  
  <p>On a hunch I changed the define at the top to:</p>
  
  <pre><code>#ifdef _WIN32
  //#define USEWIN32IOAPI  //disabled this
  #include "iowin32.h"
  #endif
  </code></pre>
  
  <p>Now mininunzip works fine but I dont really know why.  Anyone know if this is a known bug , I couldnt find any information about it.</p>
  
  <p>Thanks</p>