title: "Token is not a valid binary operator in a preprocessor subexpression" when using UIKitForMac
body: <p>So I'm trying to compile my iOS project for the mac, and when I try to use</p>
  
  <p><code>#if !targetEnvironment(UIKitForMac)</code></p>
  
  <p>I'm getting the error from the title. </p>
  
  <p>I tried setting the build target to iOS 13, but didn't seem to have any effect.</p>