title: what is this /build/config.gypi file and can I delete it?
body: <p>One of the libraries in node that I use obviously uses node-gyp and node-gyp apparently outputs a /build/config.gypi file (sometimes). I can't find any explanation of what this file is, <a href="https://github.com/TooTallNate/node-gyp/issues/32" rel="noreferrer">beyond this issue on github.</a> </p>
  
  <p>Will anything be impacted if I delete this file? It's easy enough to find out the hard way. Thought it would be nice if this question was answered for the next person that finds this file and goes "huh?"</p>