time-stamp: update support for time zone numeric offset

* time-stamp.el (time-stamp-string-preprocess): Change new format for
numeric time zone from %:z to %5z to match format-time-string better.
(time-stamp-format): Document support for numeric time zone.
See discussion in bug#32931.

* NEWS: Mention time-stamp-format %5z.

1 files changed, 12 insertions, 1 deletions

diff --git a/etc/NEWS b/etc/NEWS
index ff334493298..485d2b1fdf4 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -2248,7 +2248,18 @@ and 'gravatar-force-default'.
 *** The built-in ada-mode is now deleted.  The GNU ELPA package is a
 good replacement, even in very large source files.
 
-** Some conversions recommended for 'time-stamp-format' have changed.
+** time-stamp
+
+*** New '%5z' conversion for 'time-stamp-format' gives time zone offset.
+Specifying '%5z' in 'time-stamp-format' or 'time-stamp-pattern'
+expands to the time zone offset, e.g., '+0100'.  The time zone used is
+specified by 'time-stamp-time-zone'.
+
+Because this feature is new in Emacs 27.1, do not use it in the local
+variables section of any file that might be edited by an older version
+of Emacs.
+
+*** Some conversions recommended for 'time-stamp-format' have changed.
 The new documented/recommended %-conversions are closer to those
 used by 'format-time-string' and are compatible at least as far back
 as Emacs 22.1 (released in 2007).