[mutter] wayland-private: Make display_name non-const

[Florian Müllner <fmuellner src gnome org>]

commit f0c9c25cf8e1f16fa42c05b0218cd7e8a272e90e
Author: Florian Müllner <fmuellner gnome org>
Date:   Mon Jul 23 19:43:53 2018 +0200

    wayland-private: Make display_name non-const
    
    The string used to point to memory owned by libwayland-server, but
    with the ability to override the display name, we took over ownership
    by copying the string as necessary.
    
    https://gitlab.gnome.org/GNOME/mutter/merge_requests/176

 src/wayland/meta-wayland-private.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/src/wayland/meta-wayland-private.h b/src/wayland/meta-wayland-private.h
index bfb27cdf6..e2442b385 100644
--- a/src/wayland/meta-wayland-private.h
+++ b/src/wayland/meta-wayland-private.h
@@ -64,7 +64,7 @@ typedef struct
 struct _MetaWaylandCompositor
 {
   struct wl_display *wayland_display;
-  const char *display_name;
+  char *display_name;
   GHashTable *outputs;
   struct wl_list frame_callbacks;