title: Xcode build fails due to Undefined symbol: __swift_FORCE_LOAD_$_swiftUIKit
body: <p>I created a brand new project in Xcode 11 (an iOS single-view project with SwiftUI) and enable Mac as a target device. Without doing anything else, I try to build, and I get this error:</p>
  
  <pre class="lang-none prettyprint-override"><code>ld: warning: directory not found for option '-L/Applications/Xcode'
  ld: warning: directory not found for option '-L11.0-Beta.2.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/uikitformac'
  ld: warning: directory not found for option '-L/Applications/Xcode'
  ld: warning: directory not found for option '-L11.0-Beta.2.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/swift/uikitformac'
  ld: warning: Could not find or use auto-linked library 'swiftUIKit'
  Undefined symbols for architecture x86_64:
    "__swift_FORCE_LOAD_$_swiftUIKit", referenced from:
        __swift_FORCE_LOAD_$_swiftUIKit_$_MyProject in AppDelegate.o
        __swift_FORCE_LOAD_$_swiftUIKit_$_MyProject in SceneDelegate.o
        __swift_FORCE_LOAD_$_swiftUIKit_$_MyProject in ContentView.o
       (maybe you meant: __swift_FORCE_LOAD_$_swiftUIKit_$_MyProject)
  ld: symbol(s) not found for architecture x86_64
  clang: error: linker command failed with exit code 1 (use -v to see invocation)
  </code></pre>
  
  <hr>
  
  <h3>Environment</h3>
  
  <ul>
  <li>macOS 10.15 Catalina Beta (19A487l)</li>
  <li>Xcode 11.0 beta 2 (11M337n)
  
  <ul>
  <li>Swift 5 mode</li>
  </ul></li>
  </ul>