title: react-redux - ReferenceError: g is not defined
body: <p>I found this problem when was building javascript files for production and I test the Website again. In the development environment I can not reproduce.
  I am using react and react-redux on my SinglePageApplication, npm and gulp building tool.</p>
  
  <p><strong>package.json:</strong></p>
  
  <pre><code>"react": "~16.0.0",
  "react-chartjs-2": "^2.6.4",
  "react-dom": "~16.0.0",
  "react-dropzone": "^4.1.3",
  "react-popper": "^0.7.3",
  "react-redux": "~4.4.0",
  </code></pre>
  
  <p><strong>versions</strong></p>
  
  <pre><code>react -v : 16.3.0
  react-redux -v : 4.4.9
  </code></pre>
  
  <p><strong>Gulp command</strong></p>
  
  <pre><code>npm -i
  gulp production
  </code></pre>
  
  <p>I got an error message from the browser:</p>
  
  <pre><code>react-redux.min.js? 3b99:1 Uncaught     
  
  ReferenceError: g is not defined
          at a (react-redux.min.js?3b99:1)
          at a (react-redux.min.js?3b99:1)
          at react-redux.min.js?3b99:1
  </code></pre>