[O] [BUG] Void variable org-clock-current-task

[Kyle Meyer]

Hi Nicolas,

4743d43 (Properly handle ‘org-tag-persistent-alist’, 2016-04-17) removed
the initial value for org-clock-current-task:

    - (defvar org-clock-current-task nil)
    + (defvar org-clock-current-task)

As a result, org-clock-current-task is undefined if org-clock.el is not
yet loaded, leading to org-agenda-mark-clocking-task signaling a
void-variable error when org-agenda is called.

    Debugger entered--Lisp error: (void-variable org-clock-current-task)
      (if org-clock-current-task
          (progn (save-restriction ...)))
      org-agenda-mark-clocking-task()
      ...
      call-interactively(org-agenda nil nil)
      command-execute(org-agenda)

--
Kyle