title: How to set 'exclude_files' in Podfile rather than podspec
body: <p>I've created a new react-native project (0.61.5) and am trying to install <a href="https://github.com/react-native-kit/react-native-track-player" rel="nofollow noreferrer">react-native-track-player</a>. The default <a href="https://react-native-kit.github.io/react-native-track-player/install/" rel="nofollow noreferrer">installation docs</a> are pretty sparse but after going through the issues I was able to successfully get the app running, just in a hacky way.</p>
  
  <p>The solution I needed is found in <a href="https://github.com/react-native-kit/react-native-track-player/issues/503#issuecomment-578087334" rel="nofollow noreferrer">this</a> thread. Setting <code>s.exclude_files = ["ios/RNTrackPlayer/Vendor/AudioPlayer/Example"]</code> in <code>node_modules/react-native-track-player/react-native-track-player.podspec</code> works but I don't want to add it again every time my node_modules folder gets reset. </p>
  
  <p>I saw in a different <a href="https://github.com/react-native-kit/react-native-track-player/issues/673#issuecomment-579536060" rel="nofollow noreferrer">thread</a> (and ended up using this as well) that setting the swift version in the Podfile to 5 in the <code>post_install</code> method will set the proper version of swift for react-native-track-player to work. I thought maybe I could move the <code>exclude_files</code> hack from node_modules podspec file to my Podfile and solve all my problems, only it seems to not work when set there:</p>
  
  <pre><code>post_install do |installer|
    installer.pods_project.targets.each do |target|
      if ['react-native-track-player'].include? target.name
        target.build_configurations.each do |config|
          config.build_settings['SWIFT_VERSION'] = '5'
          config.build_settings['EXCLUDE_FILES'] = '../node_modules/react-native-track-player/ios/RNTrackPlayer/Vendor/AudioPlayer/Example`
        end
      end
    end
  end
  </code></pre>
  
  <p>TLDR:
  <strong>Is it possible to set exclude_files in my Podfile in the post_install call?</strong></p>