org-check-external-command
org-check-external-command is a compiled Lisp function in `org-macs.el
'.
(org-check-external-command CMD &optional USE NO-ERROR)
Check if external program CMD for USE exists, error if not.
When the program does exist, return its path.
When it does not exist and NO-ERROR is set, return nil.
Otherwise, throw an error. The optional argument USE can describe what this
program is needed for, so that the error message can be more informative.