title: Uglify with r.js throws a parsing error
body: <p>I'm using r.js to optimize/uglify my JavaScript code which is using RequireJS.</p>
  
  <p>One of my modules is a polyfill module:</p>
  
  <pre><code>define(function(){
      if (!Array.prototype.filter)
      {  /* ... */ }
  
      var isPolyfillNeeded = function () { /* ... */ }
  
      if (isPolyfillNeeded()) {
          /* polyfill implementation */
      }
  });
  </code></pre>
  
  <p>The module causes parsing error thrown from r.js when trying to uglify it, saying:</p>
  
  <pre><code>Tracing dependencies for: ../scripts/main-app
  Error: Parse error using UglifyJS for file: C:/.../polyfill.js
  Unexpected character '?' (line: .., col: .., pos: ..)
  
  undefined
  In module tree:
      ../scripts/main-main-app
        moduleA
          moduleB
  </code></pre>
  
  <p>When replacing <code>var isPolyfillNeeded = function ()</code> with <code>function isPolyfillNeeded()</code>, it works fine.
  Why is that?</p>