title: I cannot pod install
body: <p>I cannot pod install.
  This is error.
  I want u help me.</p>
  
  <pre><code> xcrun: error: SDK "iphoneos" cannot be located
      xcrun: error: SDK "iphoneos" cannot be located
      xcrun: error: SDK "iphoneos" cannot be located
      xcrun: error: unable to lookup item 'Path' in SDK 'iphoneos'
      /Users/dan/Library/Caches/CocoaPods/Pods/Release/Flipper-Glog/0.3.6-1dfd6/missing: Unknown `--is-lightweight' option
      Try `/Users/dan/Library/Caches/CocoaPods/Pods/Release/Flipper-Glog/0.3.6-1dfd6/missing --help' for more information
      configure: WARNING: 'missing' script is too old or missing
      configure: error: in `/Users/dan/Library/Caches/CocoaPods/Pods/Release/Flipper-Glog/0.3.6-1dfd6':
      configure: error: C compiler cannot create executables
      See `config.log' for more details
  </code></pre>