Document format-time-string %q

* doc/lispref/os.texi (Time Parsing):
* etc/NEWS: Document new %q functionality taken from gnulib.

doc/lispref/os.texi

@@ -1525,6 +1525,8 @@ fewer digits, use @samp{%3N} for milliseconds, @samp{%6N} for
 microseconds, etc.  Any excess digits are discarded, without rounding.
 @item %p
 This stands for @samp{AM} or @samp{PM}, as appropriate.
+@item %q
+This stands for the calendar quarter (1--4).
 @item %r
 This is a synonym for @samp{%I:%M:%S %p}.
 @item %R

etc/NEWS

@@ -689,6 +689,9 @@ ABBR is a time zone abbreviation.  The affected functions are
 'current-time-string', 'current-time-zone', 'decode-time',
 'format-time-string', and 'set-time-zone-rule'.
 
++++
+** 'format-time-string' now formats "%q" to the calendar quarter.
+
 ** New built-in function 'mapcan' which avoids unnecessary consing (and garbage
 collection).