[mutter] wayland: Don't free non-transferred string when cleaning up

[Jonas Ådahl <jadahl src gnome org>]

commit 807658e9725bd8d3693e3a7178c72546b8835e63
Author: Jonas Ådahl <jadahl gmail com>
Date:   Mon Sep 4 12:32:53 2017 +0800

    wayland: Don't free non-transferred string when cleaning up
    
    When cleaning up the display name string management, the display name
    string retrieved from libwayland-server was also passed to free() on
    clean up. This is invalid as the display name string ownership is not
    transferred to us. Fix this by strdup:ing the string before saving it.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=730551

 src/wayland/meta-wayland.c |    9 ++++++---
 1 files changed, 6 insertions(+), 3 deletions(-)
---
diff --git a/src/wayland/meta-wayland.c b/src/wayland/meta-wayland.c
index 716b7f3..2c3dff2 100644
--- a/src/wayland/meta-wayland.c
+++ b/src/wayland/meta-wayland.c
@@ -376,10 +376,13 @@ meta_wayland_init (void)
     }
   else
     {
-      compositor->display_name =
-        wl_display_add_socket_auto (compositor->wayland_display);
-      if (compositor->display_name == NULL)
+      const char *display_name;
+
+      display_name = wl_display_add_socket_auto (compositor->wayland_display);
+      if (!display_name)
         g_error ("Failed to create socket");
+
+      compositor->display_name = g_strdup (display_name);
     }
 
   set_gnome_env ("DISPLAY", meta_wayland_get_xwayland_display_name (compositor));