title: Restkit on Xcode 4.5 GM does not work on iOS 6 device - file was built for archive which is not the architecture being linked
body: <p>I have been using Xcode 4.4.1 and Restkit has been working perfectly on Simulator and Device. Since I upgraded to Xcode 4.5 yesterday, Restkit works fine on the Simulator, but when I try to run on my iOS 6 device, I get compile errors;</p>
  
  <pre><code>d: warning: ignoring file /Developer/Xcode/DerivedData/App-Name/Build/Products/Debug-iphoneos/libRestKit.a, file was built for archive which is not the architecture being linked (armv7s): /Developer/Xcode/DerivedData/App-Name/Build/Products/Debug-iphoneos/libRestKit.a
  Undefined symbols for architecture armv7s:
  
    "_OBJC_CLASS_$_RKObjectManager", referenced from:
        objc-class-ref in AppDelegate.o
  </code></pre>
  
  <p>What does this mean and how do I fix this issue? Help is appreciated.</p>