title: An *empty* PHP file "<?php", when included, doesn't get parsed and is added to Output Buffer instead, why so?
body: <p>The simplest way to replicate is through a web context, by doing:</p>
  
  <ol>
  <li><p>Create a <code>file.php</code> with the following contents: <code>&lt;?php</code>. <strong>No whitespace!</strong></p></li>
  <li><p>Make <code>index.php</code> with the following contents:</p>
  
  <pre><code>&lt;?php
  
  header('Content-Type: text/plain');
  
  require 'file.php';
  
  echo 'test';
  </code></pre></li>
  </ol>
  
  <p>Now, witness the results.</p>
  
  <p>Expected: <code>test</code></p>
  
  <p>Actual: <code>&lt;?phptest</code></p>
  
  <p>I've stumbled upon this quite some times while developing, and it's quite annoying.</p>
  
  <p>Environment:</p>
  
  <ul>
  <li>Linux 3.13.7-1-ARCH #1 SMP PREEMPT Mon Mar 24 20:06:08 CET 2014 x86_64</li>
  <li>Apache/2.4.9 (Unix) (built: Mar 16 2014 12:48:23)</li>
  <li>PHP 5.5.10 (cli) (built: Mar 5 2014 17:41:10)</li>
  </ul>
  
  <p>Why such behavior, how come PHP doesn't parse this?</p>