title: Project 'Pods' - Turn on Whole Module Optimization
body: <p>In Xcode 9 I'm getting the following suggestion for a cocoa pods project:
  <a href="https://i.stack.imgur.com/JqeB7.png" rel="noreferrer"><img src="https://i.stack.imgur.com/JqeB7.png" alt="suggestion"></a></p>
  
  <p>What does it do? And, shall I turn it on, or it will break things up?</p>