title: strtok with empty string delimiter
body: <p>I have seen the following piece of code in one of the library. What is the behavior of strtok when empty string is passed as a delimiter? I can see whatever buf contains, stored into token variable after strtok call.</p>
  
  <pre><code>char buf[256] = {0};
  char token = NULL;
  
  ...
  ...
  while (!feof(filePtr))
  {
    os_memset(buf, 0, sizeof(buf));
    if (!fgets(buf, 256, filePtr)) 
    {
      token = strtok(buf, "");
      ...
      ...
    }
  }
  </code></pre>