title: pkg-config: command not found, using cygwin on windows 7
body: <p>I'm using Cygwin on windows to run this command:</p>
  
  <pre><code> g++ `pkgconfig --libs --cflags opencv` -I. -o mergevec mergevec.cpp ....
  </code></pre>
  
  <p>But I get an error:</p>
  
  <pre><code>-bash: pkg-config: command not found
  </code></pre>
  
  <p>I've installed cygwin directly on C:. I've added to the PATH environment variable the following:</p>
  
  <pre><code>C:\cygwin64\bin;
  C:\cygwin64\lib
  </code></pre>
  
  <p>I've run <code>cygcheck -c</code> and it gives me a whole list of packages, but <code>pkg-config</code> isn't in that list.
  There is a folder called <code>pkgconfig</code> in <code>C:\cygwin64\lib</code> though.
  How do I fix this error?</p>