Take into account the initial buttons state when creating wxGTK toolbar.

With wxMSW it is possible to call e.g. wxToolBarTool::Enable(false) on a tool
before calling wxToolBar::Realize() to create the tool in an initially
disabled state but this wasn't done in wxGTK version.

Override Realize() now under wxGTK to bring the native toolbar buttons state
in sync with the internal state of the corresponding wxToolBarTools.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@62994 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/gtk/toolbar.h

@@ -51,6 +51,8 @@ public:
     virtual void SetToolNormalBitmap(int id, const wxBitmap& bitmap);
     virtual void SetToolDisabledBitmap(int id, const wxBitmap& bitmap);
 
+    virtual bool Realize();
+
     static wxVisualAttributes
     GetClassDefaultAttributes(wxWindowVariant variant = wxWINDOW_VARIANT_NORMAL);