wxWidgets compatibility fixes

* Remove unneeded check
* Fix WX_GRID since upstream renamed a variable in 3.1.3

common/widgets/wx_grid.cpp

@@ -148,7 +148,12 @@ void WX_GRID::DrawColLabel( wxDC& dc, int col )
 
     // It is reported that we need to erase the background to avoid display
     // artefacts, see #12055.
+    // wxWidgets renamed this variable between 3.1.2 and 3.1.3 ...
+#if wxCHECK_VERSION( 3, 1, 3 )
+    wxDCBrushChanger setBrush( dc, m_colLabelWin->GetBackgroundColour() );
+#else
     wxDCBrushChanger setBrush( dc, m_colWindow->GetBackgroundColour() );
+#endif
     dc.DrawRectangle(rect);
 
     rend.DrawBorder( *this, dc, rect );

include/gal/cairo/cairo_gal.h

@@ -39,16 +39,6 @@
 
 #include <memory>
 
-#if defined(__WXMSW__)
-#define SCREEN_DEPTH 24
-#else
-#if wxCHECK_VERSION( 2, 9, 0 )
-#define SCREEN_DEPTH    wxBITMAP_SCREEN_DEPTH
-#else
-#define SCREEN_DEPTH    32
-#endif
-#endif
-
 /**
  * @brief Class CAIRO_GAL is the cairo implementation of the graphics abstraction layer.
  *