title: Argument doesn't recognized if passed with QProcess
body: <p>I have difficult to pass the <code>-vo</code> argument to mplayer using <code>QProcess</code>,
  Here a minimal example:</p>
  
  <pre><code>MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow)
  {
      ui-&gt;setupUi(this);
  
      QString program;
      program = "C:\\mplayer-svn-38008\\mplayer.exe";
  
      QStringList arguments;
      arguments &lt;&lt; "-vo gl" &lt;&lt; "C:\\test.mp4"; 
  
      QProcess *m_process = new QProcess(this);
      m_process-&gt;start(program, arguments);
  }
  </code></pre>
  
  <p>The process outputs:</p>
  
  <blockquote>
    <p>Unknown option on the command line: -vo gl</p>
  </blockquote>
  
  <p>using the same argument on Windows shell leads to the correct behavior:</p>
  
  <pre><code>&gt;mplayer -vo gl C:/test.mp4
  </code></pre>
  
  <p>Also, removing that argument from the <code>QStringList</code> works.
  Why the <code>-vo</code> option is recognized from command line but not from <code>QProcess</code>?</p>