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 -ur a/daemon/gdm-session.c b/daemon/gdm-session.c
--- a/daemon/gdm-session.c	2019-09-25 10:40:24.000000000 -0400
+++ b/daemon/gdm-session.c	2020-04-18 18:30:02.671856808 -0400
@@ -348,24 +348,18 @@
         GArray *search_array = NULL;
         char **search_dirs;
         int i;
-        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 con</td></tr></table>
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