Add FIXMEs for subsecond support

This adds FIXMEs to areas where Lisp code should support
subsecond information in broken-down timestamps.
It also fixes some unnecessary truncation of timestamps, and
ports the code to a hypothetical future Emacs version where
(decode-time) returns subsecond timestamps by default.
* lisp/calc/calc-forms.el (calc-time, math-iso-dt-to-date)
(calcFunc-now):
* lisp/calendar/icalendar.el (icalendar--add-decoded-times):
* lisp/calendar/iso8601.el (iso8601-parse-interval):
Truncate seconds to an integer, and add a FIXME about
subseconds support.
* lisp/calendar/icalendar.el (icalendar--decode-isodatetime)
(icalendar--decode-isoduration):
Add a FIXME about subseconds support.
* lisp/gnus/gnus-delay.el (gnus-delay-article):
Don’t truncate seconds to an integer, as there’s no need
to do that here.
* lisp/gnus/gnus-util.el (gnus-seconds-today)
(gnus-seconds-month, gnus-seconds-year):
* lisp/gnus/message.el (message-make-expires-date):
* lisp/org/org-timer.el (org-timer-show-remaining-time):
* lisp/vc/ediff-mult.el (ediff-format-date):
Truncate seconds to an integer, as that’s what’s wanted here.
* lisp/midnight.el (midnight-next):
Ceiling seconds to an integer, as that’s what wanted here.

1 files changed, 6 insertions, 6 deletions

diff --git a/lisp/gnus/gnus-util.el b/lisp/gnus/gnus-util.el
index c6be59fd19f..f73af8e261c 100644
--- a/lisp/gnus/gnus-util.el
+++ b/lisp/gnus/gnus-util.el
@@ -357,24 +357,24 @@ Symbols are also allowed; their print names are used instead."
 ;; the full date if it's older)
 
 (defun gnus-seconds-today ()
-  "Return the number of seconds passed today."
-  (let ((now (decode-time)))
+  "Return the integer number of seconds passed today."
+  (let ((now (decode-time nil nil 'integer)))
     (+ (decoded-time-second now)
        (* (decoded-time-minute now) 60)
        (* (decoded-time-hour now) 3600))))
 
 (defun gnus-seconds-month ()
-  "Return the number of seconds passed this month."
-  (let ((now (decode-time)))
+  "Return the integer number of seconds passed this month."
+  (let ((now (decode-time nil nil 'integer)))
     (+ (decoded-time-second now)
        (* (decoded-time-minute now) 60)
        (* (decoded-time-hour now) 3600)
        (* (- (decoded-time-day now) 1) 3600 24))))
 
 (defun gnus-seconds-year ()
-  "Return the number of seconds passed this year."
+  "Return the integer number of seconds passed this year."
   (let* ((current (current-time))
-	 (now (decode-time current))
+	 (now (decode-time current nil 'integer))
 	 (days (format-time-string "%j" current)))
     (+ (decoded-time-second now)
        (* (decoded-time-minute now) 60)