[gtk/gtk-2-24] Update GDK_OSX versions to current MacOS release.

[John Ralls <jralls src gnome org>]

commit 74d71480896ca573be376df095548475f458424d
Author: John Ralls <jralls ceridwen us>
Date:   Mon Oct 15 10:41:15 2018 -0700

    Update GDK_OSX versions to current MacOS release.

 gdk/quartz/gdkquartz.h | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
---
diff --git a/gdk/quartz/gdkquartz.h b/gdk/quartz/gdkquartz.h
index 70155c0d38..8206db0197 100644
--- a/gdk/quartz/gdkquartz.h
+++ b/gdk/quartz/gdkquartz.h
@@ -48,7 +48,13 @@ typedef enum
   GDK_OSX_SNOW_LEOPARD = 6,
   GDK_OSX_LION = 7,
   GDK_OSX_MOUNTAIN_LION = 8,
-  GDK_OSX_CURRENT = 8,
+  GDK_OSX_MAVERICKS = 9,
+  GDK_OSX_YOSEMITE = 10,
+  GDK_OSX_EL_CAPITAN = 11,
+  GDK_OSX_SIERRA = 12,
+  GDK_OSX_HIGH_SIERRA = 13,
+  GDK_OSX_MOJAVE = 14,
+  GDK_OSX_CURRENT = 14,
   GDK_OSX_NEW = 99
 } GdkOSXVersion;