Updates to fix Watcom C/C++ 11.0 compiler warning problems. Now compiles

clean with this compiler. Hopefully I did this without breaking other
compilers.


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@9967 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/msw/listbox.cpp

@@ -100,7 +100,7 @@ wxListBoxItem::wxListBoxItem(const wxString& str) : wxOwnerDrawn(str, FALSE)
     SetMarginWidth(0);
 }
 
-wxOwnerDrawn *wxListBox::CreateItem(size_t n)
+wxOwnerDrawn *wxListBox::CreateItem(size_t WXUNUSED(n))
 {
     return new wxListBoxItem();
 }