show_date_relative(): drop unused "tz" parameter

The timestamp we receive is in epoch time, so there's no need for a
timezone parameter to interpret it. The matching show_date() uses "tz"
to show dates in author local time, but relative dates show only the
absolute time difference. The author's location is irrelevant, barring
relativistic effects from using Git close to the speed of light.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

cache.h

@@ -1464,7 +1464,7 @@ struct date_mode {
 struct date_mode *date_mode_from_type(enum date_mode_type type);
 
 const char *show_date(timestamp_t time, int timezone, const struct date_mode *mode);
-void show_date_relative(timestamp_t time, int tz, const struct timeval *now,
+void show_date_relative(timestamp_t time, const struct timeval *now,
 			struct strbuf *timebuf);
 int parse_date(const char *date, struct strbuf *out);
 int parse_date_basic(const char *date, timestamp_t *timestamp, int *offset);

date.c

@@ -107,9 +107,9 @@ static int local_tzoffset(timestamp_t time)
 	return offset * eastwest;
 }
 
-void show_date_relative(timestamp_t time, int tz,
-			       const struct timeval *now,
-			       struct strbuf *timebuf)
+void show_date_relative(timestamp_t time,
+			const struct timeval *now,
+			struct strbuf *timebuf)
 {
 	timestamp_t diff;
 	if (now->tv_sec < time) {
@@ -216,7 +216,7 @@ const char *show_date(timestamp_t time, int tz, const struct date_mode *mode)
 
 		strbuf_reset(&timebuf);
 		gettimeofday(&now, NULL);
-		show_date_relative(time, tz, &now, &timebuf);
+		show_date_relative(time, &now, &timebuf);
 		return timebuf.buf;
 	}
 

t/helper/test-date.c

@@ -16,7 +16,7 @@ static void show_relative_dates(const char **argv, struct timeval *now)
 
 	for (; *argv; argv++) {
 		time_t t = atoi(*argv);
-		show_date_relative(t, 0, now, &buf);
+		show_date_relative(t, now, &buf);
 		printf("%s -> %s\n", *argv, buf.buf);
 	}
 	strbuf_release(&buf);