[gtk+] Remove a dead macro

[Matthias Clasen <matthiasc src gnome org>]

commit 0ed670ed623c4c91df1393f8fa1cbbaca6366468
Author: Matthias Clasen <mclasen redhat com>
Date:   Thu Jan 4 18:23:36 2018 -0500

    Remove a dead macro
    
    GCs have been dead for a long time.

 gdk/x11/gdkprivate-x11.h |    1 -
 1 files changed, 0 insertions(+), 1 deletions(-)
---
diff --git a/gdk/x11/gdkprivate-x11.h b/gdk/x11/gdkprivate-x11.h
index 2cc7d7c..16acf68 100644
--- a/gdk/x11/gdkprivate-x11.h
+++ b/gdk/x11/gdkprivate-x11.h
@@ -246,7 +246,6 @@ extern const gint        _gdk_x11_event_mask_table_size;
 #define GDK_WINDOW_SCREEN(win)        (GDK_X11_DISPLAY (gdk_window_get_display (win))->screen)
 #define GDK_WINDOW_DISPLAY(win)       (gdk_window_get_display (win))
 #define GDK_WINDOW_XROOTWIN(win)      (GDK_X11_SCREEN (GDK_WINDOW_SCREEN (win))->xroot_window)
-#define GDK_GC_DISPLAY(gc)            (GDK_SCREEN_DISPLAY (GDK_GC_X11(gc)->screen))
 #define GDK_WINDOW_IS_X11(win)        (GDK_IS_WINDOW_IMPL_X11 ((win)->impl))
 
 /* override some macros from gdkx.h with direct-access variants */