[gtk/gtk-3-24] Accommodate macOS 11.0 Big Sur in gdk_quartz_osx_version.

[John Ralls <jralls src gnome org>]

commit 69135bcfe3c6e907e3dfed23d97eae9abfd782bc
Author: John Ralls <jralls ceridwen us>
Date:   Tue Aug 11 17:05:10 2020 -0700

    Accommodate macOS 11.0 Big Sur in gdk_quartz_osx_version.
    
    This may need to be changed next year, it depends on what Apple
    decides to do with version numbers going forward.
    
    Also updated GdkOSXVersion to include Catalina and Big Sur.

 gdk/quartz/gdkglobals-quartz.c | 2 ++
 gdk/quartz/gdkquartz.h         | 4 +++-
 2 files changed, 5 insertions(+), 1 deletion(-)
---
diff --git a/gdk/quartz/gdkglobals-quartz.c b/gdk/quartz/gdkglobals-quartz.c
index 46a4c811aa..72aed1c92d 100644
--- a/gdk/quartz/gdkglobals-quartz.c
+++ b/gdk/quartz/gdkglobals-quartz.c
@@ -42,6 +42,8 @@ gdk_quartz_osx_version (void)
 
       version = [[NSProcessInfo processInfo] operatingSystemVersion];
       minor = version.minorVersion;
+      if (version.majorVersion == 11)
+        minor += 16;
 #endif
     }
 
diff --git a/gdk/quartz/gdkquartz.h b/gdk/quartz/gdkquartz.h
index b6bce2b140..dd1b4f41af 100644
--- a/gdk/quartz/gdkquartz.h
+++ b/gdk/quartz/gdkquartz.h
@@ -40,7 +40,9 @@ typedef enum
   GDK_OSX_SIERRA = 12,
   GDK_OSX_HIGH_SIERRA = 13,
   GDK_OSX_MOJAVE = 14,
-  GDK_OSX_CURRENT = 14,
+  GDK_OSX_CATALINA = 15,
+  GDK_OSX_BIGSUR = 16,
+  GDK_OSX_CURRENT = 15,
   GDK_OSX_NEW = 99
 } GdkOSXVersion;