title: Convert Str (hex int) to Dec Int
body: <p>I have a hexadecimal string value. I want to convert it to an integer. </p>
  
  <pre><code>function HexStrToInt(const str: string): Integer;
  begin
    Result := ??;
  end;
  </code></pre>
  
  <p>such that <code>HexStrToInt('22')</code>, for example, returns <code>34</code>.</p>