refactor(tazjin/gio-list-apps): refactor into dynamic Emacs module

Instead of producing a binary that gets called by Emacs, with
input/output serialisation, use a dynamic Emacs module that lets Emacs
more-or-less directly call the relevant GTK functions.

I'm doing this mostly as an experiment. Might be interesting to end up
with a dynamic module that I can dump some experimental code into that
improves my workflows.

To do this, I've exposed the emacs binary used by my Emacs
configuration in an additional `passthru` field. This ensures that the
module is linked against the right version of Emacs.

Change-Id: I1426994fe3455ed1b2a685c5a09705e29fa40950
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9163
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>
Autosubmit: tazjin <tazjin@tvl.su>

users/tazjin/emacs/config/functions.el

@@ -2,6 +2,8 @@
 (require 'dash)
 (require 'map)
 
+(require 'gio-list-apps) ;; native module!
+
 (defun goto-line-with-feedback ()
   "Show line numbers temporarily, while prompting for the line number input"
   (interactive)
@@ -336,12 +338,7 @@ names, instead of only their names (which might change)."
   "Use `//users/tazjin/gio-list-apps' to retrieve a list of
 installed (and visible) XDG apps, and let users launch them."
   (interactive)
-  (let* ((apps-json (s-lines (s-trim (shell-command-to-string "gio-list-apps"))))
-         (apps (seq-map (lambda (app)
-                          (let ((parsed (json-parse-string app :object-type 'alist)))
-                            (cons (cdr (assoc 'name parsed))
-                                  (cdr (assoc 'commandline parsed)))))
-                        apps-json))
+  (let* ((apps (taz-list-xdg-apps))
 
          ;; Display the command that will be run as an annotation
          (completion-extra-properties