title: PHP CLI doesn't use stderr to output errors
body: <p>I'm running the PHP CLI through a NSTask in MacOS, but this question is more about the CLI itself.</p>
  
  <p>I'm listening to the <code>stderr</code> pipe, but nothing is output there no matter what file I try to run:</p>
  
  <ul>
  <li>If the file type is not a plain text, <code>stdout</code> sets to <code>?</code>.  </li>
  <li>If the file is a php script with errors, the error messages are still printed to <code>stdout</code>.  </li>
  </ul>
  
  <p>Is there a switch to the interpreter to handle errors through <code>stderr</code>? Do I have an option to detect errors other than parsing <code>stdout</code>?</p>