Fix for C23.

--- remind-03.01.13/src/calendar.c	2011-12-05 22:08:21.000000000 +0000
+++ remind-03.01.13/src/calendar.c	2025-07-05 15:08:14.759695205 +0100
@@ -277,7 +277,7 @@
 /*  Write a calendar for a single week                         */
 /*                                                             */
 /***************************************************************/
-static void DoCalendarOneWeek(nleft)
+static void DoCalendarOneWeek(int nleft)
 {
     int y, m, d, done, i, l, wd;
     char buf[81];