diff -ur tz2011j.mod1/zic.c tz2011j.mod2/zic.c
--- tz2011j.mod1/zic.c	2011-10-11 21:34:44.000000000 +0100
+++ tz2011j.mod2/zic.c	2011-10-11 22:56:40.000000000 +0100
@@ -1968,8 +1968,11 @@
 		** presume this is a zone handled on a year-by-year basis;
 		** do not try to apply a rule to the zone.
 		*/
-		if (stdrp != NULL && stdrp->r_hiyear == 2037)
+		if (stdrp != NULL && stdrp->r_hiyear == 2037) {
+			result[0] = '!';
+			result[1] = '\0';
 			return;
+		}
 	}
 	if (stdrp == NULL && (zp->z_nrules != 0 || zp->z_stdoff != 0))
 		return;
@@ -2023,6 +2026,7 @@
 	register int			max_abbr_len;
 	register int			max_envvar_len;
 	register int			prodstic; /* all rules are min to max */
+	register int			do_extend;
 
 	max_abbr_len = 2 + max_format_len + max_abbrvar_len;
 	max_envvar_len = 2 * max_abbr_len + 5 * 9;
@@ -2067,6 +2071,9 @@
 	** Generate lots of data if a rule can't cover all future times.
 	*/
 	stringzone(envvar, zpfirst, zonecount);
+	do_extend = envvar[0] == '\0';
+	if(envvar[0] == '!' && envvar[1] == '\0')
+		envvar[0] = '\0';
 	if (noise && envvar[0] == '\0') {
 		register char *	wp;
 
@@ -2076,7 +2083,7 @@
 		warning(wp);
 		ifree(wp);
 	}
-	if (envvar[0] == '\0') {
+	if (do_extend) {
 		if (min_year >= INT_MIN + YEARSPERREPEAT)
 			min_year -= YEARSPERREPEAT;
 		else	min_year = INT_MIN;
@@ -2257,6 +2264,45 @@
 				starttime = tadd(starttime, -gmtoff);
 		}
 	}
+	if (do_extend) {
+		/*
+		** If we're extending the explicitly listed observations
+		** for 400 years because we can't fill the POSIX-TZ field,
+		** check whether we actually ended up explicitly listing
+		** observations through that period.  If there aren't any
+		** near the end of the 400-year period, add a redundant
+		** one at the end of the final year, to make it clear
+		** that we are claiming to have definite knowledge of
+		** the lack of transitions up to that point.
+		*/
+		struct rule xr;
+		int i;
+		struct attype *lastat;
+		xr.r_month = TM_JANUARY;
+		xr.r_dycode = DC_DOM;
+		xr.r_dayofmonth = 1;
+		xr.r_tod = 0;
+		for (lastat = &attypes[0], i = 1; i <= timecnt; i++)
+			if (attypes[i].at > lastat->at)
+				lastat = &attypes[i];
+		if (lastat->at < rpytime(&xr, max_year - 1)) {
+			/*
+			** Create new type code for the redundant entry,
+			** to prevent it being optimised away.
+			*/
+			if (typecnt >= TZ_MAX_TYPES) {
+				error(_("too many local time types"));
+				exit(EXIT_FAILURE);
+			}
+			gmtoffs[typecnt] = gmtoffs[lastat->type];
+			isdsts[typecnt] = isdsts[lastat->type];
+			ttisstds[typecnt] = ttisstds[lastat->type];
+			ttisgmts[typecnt] = ttisgmts[lastat->type];
+			abbrinds[typecnt] = abbrinds[lastat->type];
+			++typecnt;
+			addtt(rpytime(&xr, max_year + 1), typecnt-1);
+		}
+	}
 	writezone(zpfirst->z_name, envvar);
 	ifree(startbuf);
 	ifree(ab);