title: Error while configuring libpng: "zlib not installed"
body: <p>OS: Win7, using MinGW, sh.exe from MSYS  </p>
  
  <pre><code>./configure --prefix=/mingw
  </code></pre>
  
  <p>with and without prefix ends like this:</p>
  
  <pre><code>checking for zlibVersion in -lz... no
  checking for yeszlibVersion in -lz... no
  configure: error: zlib not installed
  </code></pre>
  
  <p>i've installed zlib through cmake, it went smoothly and without errors, so i have all zlib files in my bin, lib and include folders<br>
  what can be the problem? how do i fix this?</p>
  
  <p><strong>UPD</strong><br>
  looks like it's because i have libzlib.dll and not libz.dll in bin folder, but that's how it installed and i still don't know how to fix it</p>