title: circular imports with webpack returning empty object
body: <p>Hitting this exact problem currently:</p>
  
  <pre class="lang-none prettyprint-override"><code>FileA:
  var b = require file B
  var c = require file C
  
  FileB:
  var a = require file A
  
  FileC:
  var a = require file A
  </code></pre>
  
  <p>When I run the code, I get an error in File C:</p>
  
  <pre class="lang-none prettyprint-override"><code>A.doSomething is not a function
  </code></pre>
  
  <p>Threw a debugger in there and saw that A is an empty object. What's <strong>really</strong> weird is that I'm only getting an error in File C, but not File B. Super confused here.</p>