Make wxTaskBarIcon's ctor have the same API on all platforms even though setting the icon type can only be done on wxOSX-cocoa

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@71242 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/gtk/taskbar.cpp

@@ -266,7 +266,7 @@ void wxTaskBarIcon::Private::size_allocate(int width, int height)
 
 IMPLEMENT_DYNAMIC_CLASS(wxTaskBarIcon, wxEvtHandler)
 
-wxTaskBarIcon::wxTaskBarIcon()
+wxTaskBarIcon::wxTaskBarIcon(wxTaskBarIconType WXUNUSED(iconType))
 {
     m_priv = new Private(this);
 }