title: openwrt buildroot build_dir and staging_dir
body: <p>I am confused about <code>build_dir</code> and <code>staging_dir</code> in openwrt buildroot.
  What are they used for?</p>
  
  <p>There are <code>feeds</code> in openwrt. I would imagine to build an image. You will select the packages you want in <code>menuconfig</code> and use <code>make</code> to build it. </p>
  
  <p>The packages are fetched from <code>feeds</code> and then compiled into <code>build_dir</code>?</p>
  
  <p>Then what is <code>staging_dir</code> used for?</p>