Allow unsetting wxMenuItem as start of radio group too.

This must be called if another radio item is inserted before the current
starting one.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74547 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/osx/menuitem_osx.cpp

@@ -218,9 +218,9 @@ void wxMenuItem::UpdateItemText()
 // radio group stuff
 // -----------------
 
-void wxMenuItem::SetAsRadioGroupStart()
+void wxMenuItem::SetAsRadioGroupStart(bool start)
 {
-    m_isRadioGroupStart = true;
+    m_isRadioGroupStart = start;
 }
 
 void wxMenuItem::SetRadioGroupStart(int start)