From 0ce4db6fd2bfb8142fc63219b892e000a4017541 Mon Sep 17 00:00:00 2001
From: millert <millert@openbsd.org>
Date: Mon, 15 Sep 2025 19:37:35 +0000
Subject: [PATCH] rcs_set_tz: Use timegm() to parse broken-down UTC

We used to use mktime() (which expects local time not UTC) and
manually adjust the time zone, but this did not take DST into
account.  From Tomas Rippl
---
 usr.bin/rcs/rcstime.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/usr.bin/rcs/rcstime.c b/usr.bin/rcs/rcstime.c
index 1e886631402..ee2f8238632 100644
--- a/usr.bin/rcs/rcstime.c
+++ b/usr.bin/rcs/rcstime.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: rcstime.c,v 1.6 2016/08/26 09:02:54 guenther Exp $	*/
+/*	$OpenBSD: rcstime.c,v 1.7 2025/09/15 19:37:35 millert Exp $	*/
 /*
  * Copyright (c) 2006 Joris Vink <joris@openbsd.org>
  * All rights reserved.
@@ -42,9 +42,9 @@ rcs_set_tz(char *tz, struct rcs_delta *rdp, struct tm *tb)
 	time_t now;
 
 	if (!strcmp(tz, "LT")) {
-		now = mktime(&rdp->rd_date);
+		/* rd_date is stored in UTC, convert to local time. */
+		now = timegm(&rdp->rd_date);
 		ltb = localtime(&now);
-		ltb->tm_hour += ((int)ltb->tm_gmtoff/3600);
 		memcpy(tb, ltb, sizeof(*tb));
 	} else {
 		pos = 0;