org.el (org-deadline, org-schedule): Set the warning/delay relatively to the timestamp

* org.el (org-deadline, org-schedule): When called with two
universal prefix arguments, set the warning time or the delay
relatively to the current timestamp, not to today's date.

Thanks to Sébastien Vauban for reporting this.

lisp/org.el

@@ -12605,7 +12605,7 @@ of `org-todo-keywords-1'."
     (message "%d TODO entries found"
 	     (org-occur (concat "^" org-outline-regexp " *" kwd-re )))))
 
-(defun org-deadline (&optional arg time)
+(defun org-deadline (arg &optional time)
   "Insert the \"DEADLINE:\" string with a timestamp to make a deadline.
 With one universal prefix argument, remove any deadline from the item.
 With two universal prefix arguments, prompt for a warning delay.
@@ -12621,6 +12621,7 @@ can either be an Org date like \"2011-07-24\" or a delta like \"+2d\"."
 	 org-loop-over-headlines-in-active-region
 	 cl (if (outline-invisible-p) (org-end-of-subtree nil t))))
     (let* ((old-date (org-entry-get nil "DEADLINE"))
+	   (old-date-time (org-time-string-to-time old-date))
 	   (repeater (and old-date
 			  (string-match
 			   "\\([.+-]+[0-9]+[hdwmy]\\(?:[/ ][-+]?[0-9]+[hdwmy]\\)?\\) ?"
@@ -12643,11 +12644,12 @@ can either be an Org date like \"2011-07-24\" or a delta like \"+2d\"."
 		(replace-match
 		 (concat org-deadline-string
 			 " <" rpl
-			 (format " -%dd" (abs
-					  (- (time-to-days
-					      (save-match-data
-						(org-read-date nil t nil "Warn starting from")))
-					     (time-to-days nil))))
+			 (format " -%dd"
+				 (abs
+				  (- (time-to-days
+				      (save-match-data
+					(org-read-date nil t nil "Warn starting from" old-date-time)))
+				     (time-to-days old-date-time))))
 			 ">") t t))
 	    (user-error "No deadline information to update"))))
        (t
@@ -12672,7 +12674,7 @@ can either be an Org date like \"2011-07-24\" or a delta like \"+2d\"."
 			    (substring org-last-inserted-timestamp -1))))))
 	(message "Deadline on %s" org-last-inserted-timestamp))))))
 
-(defun org-schedule (&optional arg time)
+(defun org-schedule (arg &optional time)
   "Insert the SCHEDULED: string with a timestamp to schedule a TODO item.
 With one universal prefix argument, remove any scheduling date from the item.
 With two universal prefix arguments, prompt for a delay cookie.
@@ -12688,6 +12690,7 @@ either be an Org date like \"2011-07-24\" or a delta like \"+2d\"."
 	 org-loop-over-headlines-in-active-region
 	 cl (if (outline-invisible-p) (org-end-of-subtree nil t))))
     (let* ((old-date (org-entry-get nil "SCHEDULED"))
+	   (old-date-time (org-time-string-to-time old-date))
 	   (repeater (and old-date
 			  (string-match
 			   "\\([.+-]+[0-9]+[hdwmy]\\(?:[/ ][-+]?[0-9]+[hdwmy]\\)?\\) ?"
@@ -12711,11 +12714,12 @@ either be an Org date like \"2011-07-24\" or a delta like \"+2d\"."
 		(replace-match
 		 (concat org-scheduled-string
 			 " <" rpl
-			 (format " -%dd" (abs
-					  (- (time-to-days
-					      (save-match-data
-						(org-read-date nil t nil "Delay until")))
-					     (time-to-days nil))))
+			 (format " -%dd"
+				 (abs
+				  (- (time-to-days
+				      (save-match-data
+					(org-read-date nil t nil "Delay until" old-date-time)))
+				     (time-to-days old-date-time))))
 			 ">") t t))
 	    (user-error "No scheduled information to update"))))
        (t