title: Undefined symbols for architecture armv7: "_OBJC_CLASS_$_GGLContext", referenced from: objc-class-ref in AppDelegate.o
body: <p>I am trying to add Google Analytics in my iSO app and I am using Google Analytics latest SDK 
  <a href="https://developers.google.com/analytics/devguides/collection/ios/v3/" rel="noreferrer">https://developers.google.com/analytics/devguides/collection/ios/v3/</a>.</p>
  
  <p>Added all required header and frameworks to my project successfully. But while running my app I am getting below errors</p>
  
  <ol>
  <li><p>(null): "_OBJC_CLASS_$_GGLContext", referenced from:objc-class-ref in AppDelegate.o</p></li>
  <li><p>(null): Linker command failed with exit code 1 (use -v to see invocation) </p></li>
  </ol>
  
  <p>Below is the code which I am writtig in AppDelegate.m file</p>
  
  <pre><code>// Configure tracker from GoogleService-Info.plist.
  NSError *configureError;
  [[GGLContext sharedInstance] configureWithError:&amp;configureError];
  NSAssert(!configureError, @"Error configuring Google services: %@", configureError);
  
  // Optional: configure GAI options.
  GAI *gai = [GAI sharedInstance];
  gai.trackUncaughtExceptions = YES;  // report uncaught exceptions
  gai.logger.logLevel = kGAILogLevelVerbose;  // remove before app release
  </code></pre>
  
  <p>Also includes  (_OBJC_CLASS_$_GIDSignInButton and _OBJC_CLASS_$_GIDSignIn)
  Please tell what I am missing. Thanks in advance.</p>