Bring xdg-utils up to date with upstream repository.

scripts/xdg-screensaver

Index: scripts/xdg-screensaver
===================================================================
--- scripts/xdg-screensaver	(revision 84895)
+++ scripts/xdg-screensaver	(working copy)
@@ -392,14 +392,33 @@
     # see https://bugs.freedesktop.org/show_bug.cgi?id=34164
     unset GREP_OPTIONS
 
-    if [ x"$KDE_FULL_SESSION" = x"true" ]; then DE=kde;
-    elif [ x"$GNOME_DESKTOP_SESSION_ID" != x"" ]; then DE=gnome;
-    elif `dbus-send --print-reply --dest=org.freedesktop.DBus /org/freedesktop/DBus org.freedesktop.DBus.GetNameOwner string:org.gnome.SessionManager > /dev/null 2>&1` ; then DE=gnome;
-    elif xprop -root _DT_SAVE_MODE 2> /dev/null | grep ' = \"xfce4\"$' >/dev/null 2>&1; then DE=xfce;
-    elif xprop -root 2> /dev/null | grep -i '^xfce_desktop_window' >/dev/null 2>&1; then DE=xfce
+    if [ -n "${XDG_CURRENT_DESKTOP}" ]; then
+      case "${XDG_CURRENT_DESKTOP}" in
+         GNOME)
+           DE=gnome;
+           ;;
+         KDE)
+           DE=kde;
+           ;;
+         LXDE)
+           DE=lxde;
+           ;;
+         XFCE)
+           DE=xfce
+      esac
     fi
 
     if [ x"$DE" = x"" ]; then
+      # classic fallbacks
+      if [ x"$KDE_FULL_SESSION" = x"true" ]; then DE=kde;
+      elif [ x"$GNOME_DESKTOP_SESSION_ID" != x"" ]; then DE=gnome;
+      elif `dbus-send --print-reply --dest=org.freedesktop.DBus /org/freedesktop/DBus org.freedesktop.DBus.GetNameOwner string:org.gnome.SessionManager > /dev/null 2>&1` ; then DE=gnome;
+      elif xprop -root _DT_SAVE_MODE 2> /dev/null | grep ' = \"xfce4\"$' >/dev/null 2>&1; then DE=xfce;
+      elif xprop -root 2> /dev/null | grep -i '^xfce_desktop_window' >/dev/null 2>&1; then DE=xfce
+      fi
+    fi
+
+    if [ x"$DE" = x"" ]; then
       # fallback to checking $DESKTOP_SESSION
       case "$DESKTOP_SESSION" in
          gnome)