title: Update to XCode 8.3.1: Apple Mach-O Linker Error Group with Snapkit error
body: <p>Just updated to Xcode 8.3.1 and build my project get the errors like:</p>
  
  <pre><code> "__TFE7SnapKitPS_23ConstraintAttributesDSLg6heightCS_14ConstraintItem", referenced from:
  
    "__TFE7SnapKitPS_23ConstraintAttributesDSLg5widthCS_14ConstraintItem", referenced from:
  
    "__TFE7SnapKitPS_23ConstraintAttributesDSLg6centerCS_14ConstraintItem", referenced from:
  
    "__TFE7SnapKitPS_23ConstraintAttributesDSLg7centerXCS_14ConstraintItem", referenced from:
  
    "__TFE7SnapKitPS_23ConstraintAttributesDSLg6bottomCS_14ConstraintItem", referenced from:
  
    "__TFE7SnapKitPS_23ConstraintAttributesDSLg7leadingCS_14ConstraintItem", referenced from:
  
    "__TFE7SnapKitPS_23ConstraintAttributesDSLg7centerYCS_14ConstraintItem", referenced from:
  
    "__TFE7SnapKitPS_23ConstraintAttributesDSLg8trailingCS_14ConstraintItem", referenced from:
  
    "__TFE7SnapKitPS_23ConstraintAttributesDSLg3topCS_14ConstraintItem", referenced from:
  
  clang: error: linker command failed with exit code 1 (use -v to see invocation)
  </code></pre>
  
  <p>Seems it's SnapKit issue.</p>
  
  <ul>
  <li>Tried <code>cmd + shift + k</code></li>
  <li>Removed <code>pod 'SnapKit'</code> <code>pod install</code> and added it back still not work.</li>
  </ul>
  
  <p>If it's not version issue. How to debug/solve these kind of errors. Thanks.</p>
  
  <p><strong>EDIT</strong>
  Right click the error in project navigator, then choose <strong>Reveal in Log</strong> show more error information:</p>
  
  <pre><code>Undefined symbols for architecture x86_64:
    "__TFE7SnapKitPS_23ConstraintAttributesDSLg6heightCS_14ConstraintItem", referenced from:
        __TFFC6Auroma22AURAlarmViewController19configureBottomViewFCSo6UIViewT_U2_FC7SnapKit15ConstraintMakerT_ in AlarmViewController.o
  </code></pre>
  
  <p>I can see <code>AlarmViewController</code> called SnapKit layout methods. But still not clear why the error were there.</p>
  
  <p><strong>EDIT</strong>
  My previous Xcode should be 8.3.</p>