title: _SecTrustEvaluate linking error with Google Cardboard Unity3d SDK
body: <p>I am trying to run the demo project that comes with the Unity3d package for Google cardboard, but I keep getting this error when I build in xCode.</p>
  
  <p>Undefined symbols for architecture arm64:
    "_SecTrustEvaluate", referenced from:
        l155 in libvrunity.a(GTMSessionFetcher.o)
  ld: symbol(s) not found for architecture arm64
  clang: error: linker command failed with exit code 1 (use -v to see invocation)</p>
  
  <p>I am running Unity 5.2.0f3 and Xcode 6.4.  The only things I have in my project are the CardboardSDK and the demo project both downloaded from here: <a href="https://developers.google.com/cardboard/unity">https://developers.google.com/cardboard/unity</a></p>
  
  <p>Has anyone run into this problem before or know how to fix it?!</p>