Deprecate wxWindow::MakeModal().

Using this function was never the right way to show a modal window and it
didn't really work correctly. Instead of futilely trying to fix it, just
deprecate it.

Closes #1561.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70838 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/wincmn.cpp

@@ -1916,6 +1916,7 @@ wxWindowBase::FindWindowById( long id, const wxWindow* parent )
 // dialog oriented functions
 // ----------------------------------------------------------------------------
 
+#if WXWIN_COMPATIBILITY_2_8
 void wxWindowBase::MakeModal(bool modal)
 {
     // Disable all other windows
@@ -1932,6 +1933,7 @@ void wxWindowBase::MakeModal(bool modal)
         }
     }
 }
+#endif // WXWIN_COMPATIBILITY_2_8
 
 bool wxWindowBase::Validate()
 {