Command CompileSwiftSources failed with a nonzero exit code XCode 13

I had this problem surface in Xcode 13.0.

Mohamed Tarek‘s solution worked for me, but…

I was using cocoapods, so I needed a solution not blown away by pod install; or more specifically fixed with pod install.

Adding the following to the bottom of the Podfile resolved it.

post_install do |installer|
  installer.pods_project.targets.each do |target|
    target.build_configurations.each do |config|
    # some older pods don't support some architectures, anything over iOS 11 resolves that
      config.build_settings['IPHONEOS_DEPLOYMENT_TARGET'] = '12.0'
    end
  end
end