exec doesn't execute command if path contains whitespaces
<p>When I do something like </p>

<pre><code>exec("c:\\Program Files (x86)\\wkhtmltopdf\\wkhtmltopdf.exe --footer-center as  http://bbc.co.uk c:\\test2.pdf",$output);
</code></pre>

<p>nothing happens. File exists and the the following line returns 1.</p>

<pre><code>echo file_exists("c:\\Program Files (x86)\\wkhtmltopdf\\wkhtmltopdf.exe");
</code></pre>

<p>If I change it </p>

<pre><code> exec("d:\\wkhtmltopdf\\wkhtmltopdf.exe --footer-center as  http://bbc.co.uk c:\\test2.pdf",$output);
</code></pre>

<p>works fine. Can that be fixed?</p>
