[mutter] xwayland: Warn when autoclose-xwayland is not usable

[Marge Bot <marge-bot src gnome org>]

commit b8870a11b8fdb066bbd2ce9b07cd3abc660e9008
Author: Olivier Fourdan <ofourdan redhat com>
Date:   Fri Jan 28 09:56:24 2022 +0100

    xwayland: Warn when autoclose-xwayland is not usable
    
    The experimental feature "autoclose-xwayland" requires a couple of
    prerequisites:
    
    1. Be able to (re)start Xwayland on demand, i.e. with systemd
    2. Xwayland must support the terminate delay
    
    Add a warning message if "autoclose-xwayland" was requested but any of
    those prerequisites is not met.
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2258>

 src/wayland/meta-xwayland.c | 23 +++++++++++++++++------
 1 file changed, 17 insertions(+), 6 deletions(-)
---
diff --git a/src/wayland/meta-xwayland.c b/src/wayland/meta-xwayland.c
index f2485d2bc6..5d1846dfcd 100644
--- a/src/wayland/meta-xwayland.c
+++ b/src/wayland/meta-xwayland.c
@@ -868,14 +868,25 @@ meta_xwayland_start_xserver (MetaXWaylandManager *manager,
   args[i++] = XWAYLAND_LISTENFD;
   args[i++] = "7";
 #endif
-#ifdef HAVE_XWAYLAND_TERMINATE_DELAY
-  if (x11_display_policy == META_X11_DISPLAY_POLICY_ON_DEMAND &&
-      meta_settings_is_experimental_feature_enabled (settings,
+
+  if (meta_settings_is_experimental_feature_enabled (settings,
                                                      META_EXPERIMENTAL_FEATURE_AUTOCLOSE_XWAYLAND))
+#ifdef HAVE_XWAYLAND_TERMINATE_DELAY
+    {
+      if (x11_display_policy == META_X11_DISPLAY_POLICY_ON_DEMAND)
+        {
+          /* Terminate after a 10 seconds delay */
+          args[i++] = "-terminate";
+          args[i++] = "10";
+        }
+      else
+        {
+          g_warning ("autoclose-xwayland disabled, requires Xwayland on demand");
+        }
+    }
+#else
     {
-      /* Terminate after a 10 seconds delay */
-      args[i++] = "-terminate";
-      args[i++] = "10";
+      g_warning ("autoclose-xwayland disabled, not supported");
     }
 #endif
   for (j = 0; j <  G_N_ELEMENTS (x11_extension_names); j++)