This patch ensures '.desktop' files are picked up in the system profile
and not in the directories listed in $XDG_DATA_DIRS.  The latter includes
'gnome-session.desktop', which should be used if it's in
/run/current-system/profile, and only then.

Fixes <https://bugs.gnu.org/37831>.
diff --git a/daemon/gdm-session.c b/daemon/gdm-session.c
index 644aad022..d54406e93 100644
--- a/daemon/gdm-session.c
+++ b/daemon/gdm-session.c
@@ -378,16 +378,15 @@ get_system_session_dirs (GdmSession *self,
         GArray *search_array = NULL;
         char **search_dirs;
         int i, j;
-        const gchar * const *system_data_dirs = g_get_system_data_dirs ();
 
         static const char *x_search_dirs[] = {
                 "/etc/X11/sessions/",
                 DMCONFDIR "/Sessions/",
                 DATADIR "/gdm/BuiltInSessions/",
-                DATADIR "/xsessions/",
+                "/run/current-system/profile/share/xsessions/",
         };
 
-        static const char *wayland_search_dir = DATADIR "/wayland-sessions/";
+        static const char *wayland_search_dir = "/run/current-system/profile/share/wayland-sessions/";
 
         search_array = g_array_new (TRUE, TRUE, sizeof (char *));
 
@@ -396,11 +395,6 @@ get_system_session_dirs (GdmSession *self,
 
                 if (g_str_equal (supported_type, "x11") &&
                     (type == NULL || g_str_equal (type, supported_type))) {
-                        for (i = 0; system_data_dirs[i]; i++) {
-                                gchar *dir = g_build_filename (system_data_dirs[i], "xsessions", NULL);
-                                g_array_append_val (search_array, dir);
-                        }
-
                         g_array_append_vals (search_array, x_search_dirs, G_N_ELEMENTS (x_search_dirs));
                 }
 
@@ -408,11 +402,6 @@ get_system_session_dirs (GdmSession *self,
 #ifdef ENABLE_WAYLAND_SUPPORT
                 if (g_str_equal (supported_type, "wayland") &&
                     (type == NULL || g_str_equal (type, supported_type))) {
-                        for (i = 0; system_data_dirs[i]; i++) {
-                                gchar *dir = g_build_filename (system_data_dirs[i], "wayland-sessions", NULL);
-                                g_array_append_val (search_array, dir);
-                        }
-
                         g_array_append_val (search_array, wayland_search_dir);
                 }
 #endif
diff --git a/libgdm/gdm-sessions.c b/libgdm/gdm-sessions.c
index df8e377b7..e80acf7e4 100644
--- a/libgdm/gdm-sessions.c
+++ b/libgdm/gdm-sessions.c
@@ -347,27 +347,21 @@ collect_sessions (void)
                 "/etc/X11/sessions/",
                 DMCONFDIR "/Sessions/",
                 DATADIR "/gdm/BuiltInSessions/",
+                "/run/current-system/profile/share/xsessions/",
         };
 
         if (!supported_session_types || g_strv_contains ((const char * const *) supported_session_types, "x11")) {
                 for (i = 0; i < G_N_ELEMENTS (xorg_search_dirs); i++) {
                         g_ptr_array_add (dirs_search_array, g_strdup (xorg_search_dirs[i]));
                 }
-
-                for (i = 0; system_data_dirs[i]; i++) {
-                        session_dir = g_build_filename (system_data_dirs[i], "xsessions", NULL);
-                        g_ptr_array_add (dirs_search_array, session_dir);
-                }
         }
 #endif
 
 #ifdef ENABLE_WAYLAND_SUPPORT
 #ifdef ENABLE_USER_DISPLAY_SERVER
         if (!supported_session_types  || g_strv_contains ((const char * const *) supported_session_types, "wayland")) {
-                for (i = 0; system_data_dirs[i]; i++) {
-                        session_dir = g_build_filename (system_data_dirs[i], "wayland-sessions", NULL);
-                        g_ptr_array_add (dirs_search_array, session_dir);
-                }
+                g_ptr_array_add (dirs_search_array,
+                                 g_strdup ("/run/current-system/profile/share/wayland-sessions/"));
         }
 #endif
 #endif