title: Qt signal on buttongroup not connected
body: <p>I have a buttongroup defined with two radiobuttons</p>
  
  <pre><code>buttonGroupFFTDimension = new QButtonGroup(this);
  buttonGroupFFTDimension-&gt;addButton(ui-&gt;radioButton1D, 1);
  buttonGroupFFTDimension-&gt;addButton(ui-&gt;radioButton2D, 2);
  buttonGroupFFTDimension-&gt;setExclusive(true);
  ui-&gt;radioButton1D-&gt;setChecked(true);
  </code></pre>
  
  <p>The connect also compiles</p>
  
  <pre><code>connect(this-&gt;buttonGroupFFTDimension, static_cast&lt;void(QButtonGroup::*)(int)&gt;(&amp;QButtonGroup::buttonClicked),
          this, &amp;MainWindow::on_buttonGroupFFTDimension_buttonClicked);
  </code></pre>
  
  <p>but it throws and error at runtime</p>
  
  <pre><code>QMetaObject::connectSlotsByName: No matching signal for on_buttonGroupFFTDimension_buttonClicked(int)
  </code></pre>
  
  <p>I admit that I am not familiar with the new connect syntax, but also do not see the obvious error. What is wrong?</p>