File lightdm-xauthlocalhostname-support.patch of Package lightdm

set XAUTHLOCALHOSTNAME to localhost for local logins to avoid issues in the session in case the hostname changes

diff --git a/src/seat-xlocal.c b/src/seat-xlocal.c
--- a/src/seat-xlocal.c
+++ b/src/seat-xlocal.c
@@ -141,6 +141,7 @@ seat_xlocal_run_script (Seat *seat, Disp
     path = xserver_local_get_authority_file_path (xserver);
     process_set_env (script, "DISPLAY", xserver_get_address (XSERVER (xserver)));
     process_set_env (script, "XAUTHORITY", path);
+    process_set_env (script, "XAUTHLOCALHOSTNAME", "localhost");
     g_free (path);
 
     SEAT_CLASS (seat_xlocal_parent_class)->run_script (seat, display, script);
diff --git a/src/xserver-local.c b/src/xserver-local.c
--- a/src/xserver-local.c
+++ b/src/xserver-local.c
@@ -397,7 +397,8 @@ xserver_local_start (DisplayServer *disp
     XServerLocal *server = XSERVER_LOCAL (display_server);
     gboolean result;
     gchar *filename, *dir, *absolute_command;
-    gchar hostname[1024], *number;
+    gchar hostname[] = "localhost";
+    gchar *number;
     GString *command;
 
     g_return_val_if_fail (server->priv->xserver_process == NULL, FALSE);
@@ -438,7 +439,6 @@ xserver_local_start (DisplayServer *disp
     if (server->priv->layout)
         g_string_append_printf (command, " -layout %s", server->priv->layout);
 
-    gethostname (hostname, 1024);
     number = g_strdup_printf ("%d", xserver_get_display_number (XSERVER (server)));
     if (!server->priv->xdmcp_key)
         xserver_set_authority (XSERVER (server), xauth_new_cookie (XAUTH_FAMILY_LOCAL, (guint8*) hostname, strlen (hostname), number));
diff --git a/src/xsession.c b/src/xsession.c
--- a/src/xsession.c
+++ b/src/xsession.c
@@ -15,6 +15,7 @@
 #include <sys/stat.h>
 
 #include "xsession.h"
+#include "xserver-local.h"
 #include "configuration.h"
 #include "privileges.h"
 
@@ -35,6 +36,8 @@ xsession_new (XServer *xserver)
     session = g_object_new (XSESSION_TYPE, NULL);
     session->priv->xserver = g_object_ref (xserver);
 
+    if (IS_XSERVER_LOCAL (XSESSION (session)->priv->xserver))
+        session_set_env (SESSION (session), "XAUTHLOCALHOSTNAME", "localhost");
     session_set_env (SESSION (session), "DISPLAY", xserver_get_address (xserver));
     session_set_tty (SESSION (session), xserver_get_address (xserver));
     session_set_xdisplay (SESSION (session), xserver_get_address (xserver));