Fix wxButton::SetBitmapPosition() with GTK+ 3

Make the check for GTK+ >= 2.10 pass for GTK+ 3 too by simply not making
it in this case.

Closes #18004.

docs/changes.txt

@@ -173,6 +173,7 @@ wxGTK:
 - Make wxBORDER_NONE work for wxTextCtrl with GTK+ 3 (Adrien Tétar).
 - Apply wxTextCtrl::SetDefaultStyle() to user-entered text (Andreas Falkenhahn).
 - Fix wxTextCtrl::GetStyle() with GTK+ 3.
+- Fix wxButton::SetBitmapPosition() with GTK+ 3 (Jake Nelson).
 - Support background colour in wxDataViewCtrl attributes.
 - Improve wxSpinCtrl best size calculation.
 - Implement support for icon locations in wxMimeTypesManager (Hanmac).

src/gtk/anybutton.cpp

@@ -389,7 +389,9 @@ void wxAnyButton::DoSetBitmap(const wxBitmap& bitmap, State which)
 void wxAnyButton::DoSetBitmapPosition(wxDirection dir)
 {
 #ifdef __WXGTK210__
+#ifndef __WXGTK3__
     if ( !gtk_check_version(2,10,0) )
+#endif
     {
         GtkPositionType gtkpos;
         switch ( dir )