Bug #16717: Move from exo-csource to xdt-csource

- exo-csource is deprecated and moved to xdt-csource
- Bump minimal xdt version
- Clean autohell variables: we already require automake 1.11+ from
  configure.ac, not need to add useless AUTOMAKE_OPTION

Makefile.am

-# This file will be processed with automake-1.7 to create Makefile.in
-
-AUTOMAKE_OPTIONS = 1.7
 ACLOCAL_AMFLAGS = -I m4 ${ACLOCAL_FLAGS}
 
 NULL =

autogen.sh

 #!/bin/sh
 #
-# Copyright (c) 2002-2009 The Xfce development team. All rights reserved.
+# Copyright (c) 2002-2020 The Xfce development team. All rights reserved.
 #
 # This library is free software; you can redistribute it and/or modify it
 # under the terms of the GNU General Public License as published by the Free
@@ -23,17 +23,16 @@
 
 (type xdt-autogen) >/dev/null 2>&1 || {
   cat >&2 <<EOF
-autogen.sh: You don't seem to have the Xfce development tools (at least
-            version $XDT_REQUIRED_VERSION) installed on your system, which
-            are required to build this software.
+autogen.sh: You don't seem to have the Xfce development tools installed on your system, 
+            which are required to build this software.
             Please install the xfce4-dev-tools package first; it is available
-            from http://www.xfce.org/.
+            from your distribution or https://www.xfce.org/.
 EOF
   exit 1
 }
 
 test -d m4 || mkdir m4
 
-XDT_AUTOGEN_REQUIRED_VERSION="4.7.2" exec xdt-autogen "$@"
+XDT_AUTOGEN_REQUIRED_VERSION="4.14.0" exec xdt-autogen "$@"
 
 # vi:set ts=2 sw=2 et ai:

savers/Makefile.am

-## We require new-style dependency handling.
-AUTOMAKE_OPTIONS = 1.7
-
 NULL =
 
 AM_CPPFLAGS = \

src/Makefile.am

-## We require new-style dependency handling.
-AUTOMAKE_OPTIONS = 1.7
-
 NULL =
 
 saverdir = $(libexecdir)/xfce4-screensaver
@@ -249,13 +246,13 @@ xfce4_screensaver_preferences_LDADD = \
 if MAINTAINER_MODE
 
 xfce4-screensaver-dialog-css.h: $(srcdir)/xfce4-screensaver-dialog.css Makefile
-	$(AM_V_GEN) exo-csource --static --name=xfce4_screensaver_dialog_css $< >$@
+	$(AM_V_GEN) xdt-csource --static --name=xfce4_screensaver_dialog_css $< >$@
 
 xfce4-screensaver-dialog-ui.h: $(srcdir)/xfce4-screensaver-dialog.ui Makefile
-	$(AM_V_GEN) exo-csource --static --strip-comments --strip-content --name=xfce4_screensaver_dialog_ui $< >$@
+	$(AM_V_GEN) xdt-csource --static --strip-comments --strip-content --name=xfce4_screensaver_dialog_ui $< >$@
 
 xfce4-screensaver-preferences-ui.h: $(srcdir)/xfce4-screensaver-preferences.ui Makefile
-	$(AM_V_GEN) exo-csource --static --strip-comments --strip-content --name=xfce4_screensaver_preferences_ui $< >$@
+	$(AM_V_GEN) xdt-csource --static --strip-comments --strip-content --name=xfce4_screensaver_preferences_ui $< >$@
 
 DISTCLEANFILES = \
 	$(xfce4_screensaver_dialog_built_sources)       \