title: Webpack Require String Replacement
body: <p>Is it possible to allow a global variable as evaluated expression in <strong>webpack require</strong>?</p>
  
  <p>For Example:</p>
  
  <pre><code>global.root = path.join(__dirname, 'abc/');
  
  var x = require(root + 'x-module')
  </code></pre>
  
  <p>Or is it possible to replace 'root + \'' to any string before webpack resolves the path? such as</p>
  
  <pre><code>require(root + 'x-module')   ---&gt;    require('../abc/x-module')
  </code></pre>