title: strdup dumping core on passing NULL
body: <p>strdup(null) dumps core.</p>
  
  <p>Tried in on ubuntu and freeBSD both.</p>
  
  <p>why? Shouldn't it return null?</p>
  
  <pre><code>char *b = NULL;
  a = strdup(b);
  </code></pre>
  
  <p>This will dump core on strdup call. </p>