title: Warning message during building an R package: invalid uid value replaced by that for user 'nobody'
body: <p>I was building an R package using <code>R CMD build ABC</code> and got this warning message:</p>
  
  <pre><code>* building ‘milonga_1.0.tar.gz’
  Warning: invalid uid value replaced by that for user 'nobody'
  </code></pre>
  
  <p>I have no idea what it means. Would somebody have a brief explanation?</p>