Bring xdg-utils up to date with upstream repository.

scripts/xdg-email

 #!/bin/sh
 #---------------------------------------------
 #   xdg-email
 #
 #   Utility script to open the users favorite email program, using the
 #       RFC 2368 mailto: URI spec
 #
 #   Refer to the usage() function below for usage.
 #
 #   Copyright 2009-2010, Fathi Boudra <fabo@freedesktop.org>
@@ skipping 399 matching lines @@
 
 #--------------------------------------
 # Checks for known desktop environments
 # set variable DE to the desktop environments name, lowercase
 
 detectDE()
 {
     # 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)
            DE=gnome;
            ;;
          LXDE)
            DE=lxde; 
@@ skipping 402 matching lines @@
     ;;
 
     generic|lxde)
     open_generic "${mailto}"
     ;;
 
     *)
     exit_failure_operation_impossible "no method available for opening '${mailto}'"
     ;;
 esac