title: Xcode 10 GM libstdc++ error, can't run on simulator
body: <p>I am trying to test my apps for iOS 12. I have a iPad only app that works fine under Xcode 9. When I try to compile it for the simulator with Xcode 10 GM, the following warning appears:</p>
  
  <pre><code>URGENT: building for iOS Simulator simulator, but linking against dylib (/usr/lib/libstdc++.6.0.9.dylib) built for macOS. Note: This will be an error in the future
  </code></pre>
  
  <p>It will build, but when running it crashes with the following message:</p>
  
  <pre><code>dyld: lazy symbol binding failed: can't resolve symbol ___cxa_guard_acquire in /Users/.... /.... xxx.app because dependent dylib #1 could not be loaded.
  </code></pre>
  
  <p>I haven't done anything, it happened on the first try. </p>
  
  <p>Any ideas?</p>