title: ARCHS[@]: unbound variable in Xcode 12
body: <p>Our iOS project is built successfully in Xcode 11. However, on Xcode 12, it shows an error like this:</p>
  <pre><code>PhaseScriptExecution [CP]\ Embed\ Pods\ Frameworks /Users/NgoHoangLien/Library/Developer/Xcode/DerivedData/BeneKitten-asctqxwawireafgebpjujkfxjvcg/Build/Intermediates.noindex/BeneKitten.build/Debug-iphoneos/BeneKitten\ Dev.build/Script-6F989132ECCA2B13FEF9458F.sh (in target 'BeneKitten Dev' from project 'BeneKitten')
      cd /Users/NgoHoangLien/Project/Benekitten-iOS
      /bin/sh -c /Users/NgoHoangLien/Library/Developer/Xcode/DerivedData/BeneKitten-asctqxwawireafgebpjujkfxjvcg/Build/Intermediates.noindex/BeneKitten.build/Debug-iphoneos/BeneKitten\\\ Dev.build/Script-6F989132ECCA2B13FEF9458F.sh
  
  sent 1868986 bytes  received 70 bytes  3738112.00 bytes/sec
  total size is 1868525  speedup is 1.00
  /Users/NgoHoangLien/Project/Benekitten-iOS/Pods/Target Support Files/Pods-BeneKitten Dev/Pods-BeneKitten Dev-frameworks.sh: line 144: ARCHS[@]: unbound variable
  Command PhaseScriptExecution failed with a nonzero exit code.
  </code></pre>
  <p>I followed guides on the internet to make &quot;arm64&quot; for <code>EXCLUDED_ARCHS</code>. Delete <code>VALID_ARCHS</code>. But it still cannot compile. I hope you the senior engineers, experts like you can help me.</p>