title: 'sharedApplication' is unavailable: not available on iOS (App Extension)
body: <p>I'm building an app and developed a Today Extension for it a month or two ago. Randomly, while running it maybe the 10th time in in iOS 11 Beta, I got an error for the first time and now the entire app will not build.</p>
  
  <blockquote>
    <p>/Users/Documents/AppName/Pods/CarbonKit/CarbonKit/CarbonTabSwipeNavigation.m:622:27:
    'sharedApplication' is unavailable: not available on iOS (App
    Extension) - Use view controller based solutions where appropriate
    instead.</p>
  </blockquote>
  
  <p>The error appears in a Pod, but it's in a file that in written in Obj-C, not Swift, so it is hard to understand.</p>
  
  <p>These are the lines the error appears on:</p>
  
  <pre><code>  // Some projects use GTM_BACKGROUND_TASK_FETCHING to avoid compile-time references
    // to UIApplication.
  #if GTM_BACKGROUND_TASK_FETCHING
    return (id&lt;GTMUIApplicationProtocol&gt;) [UIApplication sharedApplication]; &lt;- error
  #else
    return nil;
  #endif
  </code></pre>
  
  <p>Could anyone give advice on how to solve this error? Any help would be immensely appreciated. Thanks a ton in advance!</p>
  
  <p>Cheers,
  Theo</p>