org-clock-x11idle-program-name: Prefer "xprintidle", when available

* lisp/org-clock.el (org-clock-x11idle-program-name): Change the
default value to "xprintidle" when its executable is available.
Fallback to previous default otherwise.  Update :package-version and
remove :version tags.
* etc/ORG-NEWS (New and changed options):
(~org-clock-x11idle-program-name~ now defaults to =xprintidle=, when available):
Document the change.

Link: https://orgmode.org/list/874jvkn1po.fsf@localhost

etc/ORG-NEWS

@@ -12,7 +12,16 @@ See the end of the file for license conditions.
 Please send Org bug reports to mailto:emacs-orgmode@gnu.org.
 
 * Version 9.7 (not released yet)
-** New options
+** New and changed options
+*** ~org-clock-x11idle-program-name~ now defaults to =xprintidle=, when available
+
+When =xprintidle= executable is available at =org-clock= load time, it
+is used as the default value for ~org-clock-x11idle-program-name~.
+The old =x11idle= default is used as the fallback.
+
+=xprintidle= is available as system package in most Linux
+distributions, unlike ancient =x11idle= that is distributed via WORG.
+
 *** New options for the "csl" citation export processor's LaTeX output
 
 The ~org-cite-csl-latex-label-separator~ and

lisp/org-clock.el

@@ -439,7 +439,9 @@ This uses the same format as `frame-title-format', which see."
   :group 'org-clock
   :type 'sexp)
 
-(defcustom org-clock-x11idle-program-name "x11idle"
+(defcustom org-clock-x11idle-program-name
+  (if (executable-find "xprintidle")
+      "xprintidle" "x11idle")
   "Name of the program which prints X11 idle time in milliseconds.
 
 you can do \"~$ sudo apt-get install xprintidle\" if you are using
@@ -448,8 +450,7 @@ a Debian-based distribution.
 Alternatively, can find x11idle.c in
 https://orgmode.org/worg/code/scripts/x11idle.c"
   :group 'org-clock
-  :version "24.4"
-  :package-version '(Org . "8.0")
+  :package-version '(Org . "9.7")
   :type 'string)
 
 (defcustom org-clock-goto-before-context 2