Make the xdg dependency optional

We now default to using `~/.cache/waybar-current-task.json` if the `xdg` package is not present.

org-clock-waybar.el

@@ -38,7 +38,7 @@
 
 ;;; Code:
 
-(require 'xdg)
+(require 'xdg nil t)
 (require 'json)
 (require 'org-clock)
 
@@ -47,7 +47,9 @@
   :group 'emacs)
 
 (defcustom org-clock-waybar-filename
-  (expand-file-name "waybar-current-task.json" (xdg-cache-home))
+  (if (fboundp 'xdg-cache-home)
+      (expand-file-name "waybar-current-task.json" (xdg-cache-home))
+    (expand-file-name "~/.cache/waybar-current-task.json"))
   "Name of the file to save task data to."
   :type 'string
   :group 'org-clock-waybar)
@@ -84,9 +86,9 @@
 (defun org-clock-waybar--get-tags ()
   "Get the tags of the currently clocked-in task."
   (when (org-clocking-p)
-    (save-window-excursion
-      (org-clock-goto)
-      (org-get-tags))))
+    (or (org-with-point-at org-clock-marker (org-get-tags))
+        "")
+    ))
 
 (defun org-clock-waybar--get-clocked-task-json ()
   "Get the currently clocked-in task’s data as a stringified JSON object.