diff -ur ../tzcode.orig/Makefile ./Makefile
--- ../tzcode.orig/Makefile	2005-06-13 11:33:54.000000000 -0700
+++ ./Makefile	2005-06-30 16:14:15.000000000 -0700
@@ -40,7 +40,7 @@
 # (and subdirectories).
 # Use an absolute path name for TZDIR unless you're just testing the software.
 
-TZDIR=		$(TOPDIR)/etc/zoneinfo
+TZDIR=		zoneinfo
 
 # The "tzselect", "zic", and "zdump" commands get installed in. . .
 
@@ -240,9 +240,11 @@
 
 ###############################################################################
 
-cc=		cc
+cc=		gcc
 CC=		$(cc) -DTZDIR=\"$(TZDIR)\"
 
+CPP=		g++
+
 TZCSRCS=	zic.c localtime.c asctime.c scheck.c ialloc.c
 TZCOBJS=	zic.o localtime.o asctime.o scheck.o ialloc.o
 TZDSRCS=	zdump.c localtime.c ialloc.c
@@ -276,7 +278,10 @@
 
 SHELL=		/bin/sh
 
-all:		tzselect zic zdump $(LIBOBJS)
+LS=		/bin/ls
+SED=		sed
+
+all:		tzselect zic zdump $(LIBOBJS) tz2icu
 
 ALL:		all date
 
@@ -309,9 +314,12 @@
 zdump:		$(TZDOBJS)
 		$(CC) $(CFLAGS) $(LFLAGS) $(TZDOBJS) $(LDLIBS) -o $@
 
-zic:		$(TZCOBJS) yearistype
+zic:		$(TZCOBJS) yearistype tz2icu.h
 		$(CC) $(CFLAGS) $(LFLAGS) $(TZCOBJS) $(LDLIBS) -o $@
 
+tz2icu:		tz2icu.cpp tz2icu.h
+		$(CPP) -W -Wall -pedantic tz2icu.cpp -o $@
+
 yearistype:	yearistype.sh
 		cp yearistype.sh yearistype
 		chmod +x yearistype
@@ -322,6 +330,9 @@
 right_only:	zic leapseconds $(TDATA)
 		$(ZIC) -y $(YEARISTYPE) -d $(TZDIR) -L leapseconds $(TDATA)
 
+icu_data:	tz2icu posix_only
+		./tz2icu zoneinfo zone.tab `$(LS) tzdata*.tar.gz | $(SED) -e "s/^tzdata//;s/\.tar\.gz$$//"`
+
 # In earlier versions of this makefile, the other two directories were
 # subdirectories of $(TZDIR).  However, this led to configuration errors.
 # For example, with posix_right under the earlier scheme,
--- zic.c.orig	2005-12-22 06:31:15.000000000 -0800
+++ zic.c	2006-01-19 19:34:06.000000000 -0800
@@ -23,6 +23,20 @@
 #define MKDIR_UMASK 0755
 #endif
 
+/* Enable extensions and modifications for ICU. */
+#define ICU
+
+/* Continue executing after link failure. Even if ICU is undefined
+ * (for vanilla zic behavior), ICU_LINKS should be defined, since zic
+ * appears to fail on the 2003 data the first time through during the
+ * linking phase. Running zic twice, with ICU_LINKS defined, causes
+ * links to be handled correctly. */
+#define ICU_LINKS
+
+#ifdef ICU
+#include "tz2icu.h"
+#endif
+
 /*
 ** On some ancient hosts, predicates like `isspace(C)' are defined
 ** only if isascii(C) || C == EOF. Modern hosts obey the C Standard,
@@ -96,8 +110,14 @@
 extern int	optind;
 
 static void	addtt P((zic_t starttime, int type));
+#ifdef ICU
+static int	addtype P((long gmtoff, long rawoff, long dstoff,
+				const char * abbr, int isdst,
+				int ttisstd, int ttisgmt));
+#else
 static int	addtype P((long gmtoff, const char * abbr, int isdst,
 				int ttisstd, int ttisgmt));
+#endif
 static void	leapadd P((zic_t t, int positive, int rolling, int count));
 static void	adjleap P((void));
 static void	associate P((void));
@@ -266,6 +286,18 @@
 	const int	l_value;
 };
 
+#ifdef ICU
+
+/* Indices into rules[] for final rules.  They will occur in pairs,
+ * with finalRules[i] occurring before finalRules[i+1] in the year.
+ * Each zone need only store a start year, a standard offset, and an
+ * index into finalRules[].  FinalRules[] are aliases into rules[]. */
+
+static const struct rule **   finalRules;
+static int                    finalRulesCount;
+
+#endif
+
 static struct lookup const *	byword P((const char * string,
 					const struct lookup * lp));
 
@@ -348,6 +380,11 @@
 	unsigned char	type;
 }			attypes[TZ_MAX_TIMES];
 static long		gmtoffs[TZ_MAX_TYPES];
+#ifdef ICU
+/* gmtoffs[i] = rawoffs[i] + dstoffs[i] */
+static long		rawoffs[TZ_MAX_TYPES];
+static long		dstoffs[TZ_MAX_TYPES];
+#endif
 static char		isdsts[TZ_MAX_TYPES];
 static unsigned char	abbrinds[TZ_MAX_TYPES];
 static char		ttisstds[TZ_MAX_TYPES];
@@ -459,6 +496,62 @@
 	exit(EXIT_FAILURE);
 }
 
+#ifdef ICU
+
+/* File into which we will write supplemental ICU data. */
+static FILE *                 icuFile;
+
+void emit_icu_zone(FILE* f, const char* zoneName, int zoneOffset,
+                   const struct rule* rule,
+                   int ruleIndex, int startYear) {
+    /* machine-readable section */
+    fprintf(f, "zone %s %d %d %s", zoneName, zoneOffset, startYear, rule->r_name);
+
+    /* human-readable section */
+    fprintf(f, " # zone %s, offset %d, year >= %d, rule %s (%d)\n",
+            zoneName, zoneOffset, startYear,
+            rule->r_name, ruleIndex);
+}
+
+void emit_icu_link(FILE* f, const char* from, const char* to) {
+    /* machine-readable section */
+    fprintf(f, "link %s %s\n", from, to);
+}
+
+static const char* DYCODE[] = {"DOM", "DOWGEQ", "DOWLEQ"};
+
+void emit_icu_rule(FILE* f, const struct rule* r, int ruleIndex) {
+    if (r->r_yrtype != NULL) {
+        warning("year types not supported by ICU");
+        fprintf(stderr, "rule %s, file %s, line %d\n",
+                r->r_name, r->r_filename, r->r_linenum);
+    }
+
+    /* machine-readable section */
+    fprintf(f, "rule %s %s %d %d %d %d %d %d %d",
+            r->r_name, DYCODE[r->r_dycode],
+            r->r_month, r->r_dayofmonth,
+            (r->r_dycode == DC_DOM ? -1 : r->r_wday),
+            r->r_tod, r->r_todisstd, r->r_todisgmt, r->r_stdoff
+            );
+
+    /* human-readable section */
+    fprintf(f, " # %d: %s, file %s, line %d",
+            ruleIndex, r->r_name, r->r_filename, r->r_linenum);
+    fprintf(f, ", mode %s", DYCODE[r->r_dycode]);
+    fprintf(f, ", %s, dom %d", mon_names[r->r_month].l_word, r->r_dayofmonth);
+    if (r->r_dycode != DC_DOM) {
+        fprintf(f, ", %s", wday_names[r->r_wday].l_word);
+    }
+    fprintf(f, ", time %d", r->r_tod);
+    fprintf(f, ", isstd %d", r->r_todisstd);
+    fprintf(f, ", isgmt %d", r->r_todisgmt);
+    fprintf(f, ", offset %ld", r->r_stdoff);
+    fprintf(f, "\n");
+}
+
+#endif
+
 static const char *	psxrules;
 static const char *	lcltime;
 static const char *	directory;
@@ -566,6 +659,14 @@
 		adjleap();
 	}
 
+#ifdef ICU
+	if ((icuFile = fopen(ICU_ZONE_FILE, "w")) == NULL) {
+            const char *e = strerror(errno);
+            (void) fprintf(stderr, _("%s: Can't open %s: %s\n"),
+                           progname, ICU_ZONE_FILE, e);
+            (void) exit(EXIT_FAILURE);
+        }
+#endif
 	for (i = optind; i < argc; ++i)
 		infile(argv[i]);
 	if (errors)
@@ -585,6 +686,9 @@
 	for (i = 0; i < nlinks; ++i) {
 		eat(links[i].l_filename, links[i].l_linenum);
 		dolink(links[i].l_from, links[i].l_to);
+#ifdef ICU
+                emit_icu_link(icuFile, links[i].l_from, links[i].l_to);
+#endif
 		if (noise)
 			for (j = 0; j < nlinks; ++j)
 				if (strcmp(links[i].l_to,
@@ -599,6 +703,11 @@
 		eat("command line", 1);
 		dolink(psxrules, TZDEFRULES);
 	}
+#ifdef ICU
+        for (i=0; i<finalRulesCount; ++i) {
+            emit_icu_rule(icuFile, finalRules[i], i);
+        }
+#endif /*ICU*/
 	return (errors == 0) ? EXIT_SUCCESS : EXIT_FAILURE;
 }
 
@@ -664,7 +773,9 @@
 			(void) fprintf(stderr,
 				_("%s: Can't link from %s to %s: %s\n"),
 				progname, fromname, toname, e);
+#ifndef ICU_LINKS
 			exit(EXIT_FAILURE);
+#endif
 		}
 	}
 	ifree(fromname);
@@ -1539,7 +1650,12 @@
 	convert(eitol(timecnt), tzh.tzh_timecnt);
 	convert(eitol(typecnt), tzh.tzh_typecnt);
 	convert(eitol(charcnt), tzh.tzh_charcnt);
+#ifdef ICU
+        * (ICUZoneinfoVersion*) &tzh.tzh_reserved = TZ_ICU_VERSION;
+        (void) strncpy(tzh.tzh_magic, TZ_ICU_MAGIC, sizeof tzh.tzh_magic);
+#else
 	(void) strncpy(tzh.tzh_magic, TZ_MAGIC, sizeof tzh.tzh_magic);
+#endif
 #define DO(field)	(void) fwrite((void *) tzh.field, \
 				(size_t) sizeof tzh.field, (size_t) 1, fp)
 	DO(tzh_magic);
@@ -1564,7 +1680,12 @@
 		(void) fwrite((void *) types, (size_t) sizeof types[0],
 			(size_t) timecnt, fp);
 	for (i = 0; i < typecnt; ++i) {
+#ifdef ICU
+		puttzcode((long) rawoffs[i], fp);
+		puttzcode((long) dstoffs[i], fp);
+#else
 		puttzcode((long) gmtoffs[i], fp);
+#endif
 		(void) putc(isdsts[i], fp);
 		(void) putc(abbrinds[i], fp);
 	}
@@ -1620,6 +1741,24 @@
 	}
 }
 
+#ifdef ICU
+
+int add_icu_final_rules(const struct rule* r1, const struct rule* r2) {
+    int i;
+
+    for (i=0; i<finalRulesCount; ++i) { /* i+=2 should work too */
+        if (r1==finalRules[i]) return i; /* [sic] pointer comparison */
+    }
+
+    finalRules = (const struct rule**) (void*) erealloc((char *) finalRules,
+                 (finalRulesCount + 2) * sizeof(*finalRules));
+    finalRules[finalRulesCount++] = r1;
+    finalRules[finalRulesCount++] = r2;
+    return finalRulesCount - 2;
+}
+
+#endif /*ICU*/
+
 static void
 outzone(zpfirst, zonecount)
 const struct zone * const	zpfirst;
@@ -1638,6 +1777,11 @@
 	register int			startttisgmt;
 	register int			type;
 	char				startbuf[BUFSIZ];
+#ifdef ICU
+        int                  finalRuleYear, finalRuleIndex;
+        const struct rule*   finalRule1;
+        const struct rule*   finalRule2;
+#endif
 
 	INITIALIZE(untiltime);
 	INITIALIZE(starttime);
@@ -1667,11 +1811,55 @@
 		eat(zp->z_filename, zp->z_linenum);
 		*startbuf = '\0';
 		startoff = zp->z_gmtoff;
+#ifdef ICU
+                finalRuleYear = finalRuleIndex = -1;
+                finalRule1 = finalRule2 = NULL;
+                if (i == (zonecount - 1)) { /* !useuntil */
+                    /* Look for exactly 2 rules that end at 'max' and
+                     * note them. Determine max(r_loyear) for the 2 of
+                     * them. */
+                    for (j=0; j<zp->z_nrules; ++j) {
+                        rp = &zp->z_rules[j];
+                        if (rp->r_hiyear == INT_MAX) {
+                            if (finalRule1 == NULL) {
+                                finalRule1 = rp;
+                                finalRuleYear = rp->r_loyear;
+                            } else if (finalRule2 == NULL) {
+                                finalRule2 = rp;
+                                if (rp->r_loyear > finalRuleYear) {
+                                    finalRuleYear = rp->r_loyear;
+                                }
+                            } else {
+                                error("more than two max rules found (ICU)");
+                                exit(EXIT_FAILURE);
+                            }
+                        }
+                    }
+                    if (finalRule1 != NULL && finalRule2 == NULL) {
+                        error("only one max rule found (ICU)");
+                        exit(EXIT_FAILURE);
+                    }
+                    if (finalRule1 != NULL) {
+                        /* Swap if necessary so finalRule1 occurs before
+                         * finalRule2 */
+                        if (finalRule1->r_month > finalRule2->r_month) {
+                            const struct rule* t = finalRule1;
+                            finalRule1 = finalRule2;
+                            finalRule2 = t;
+                        }
+                        /* Add final rule to our list */
+                        finalRuleIndex = add_icu_final_rules(finalRule1, finalRule2);
+                    }
+                }
+#endif
 		if (zp->z_nrules == 0) {
 			stdoff = zp->z_stdoff;
 			doabbr(startbuf, zp->z_format,
 				(char *) NULL, stdoff != 0);
 			type = addtype(oadd(zp->z_gmtoff, stdoff),
+#ifdef ICU
+                                zp->z_gmtoff, stdoff,
+#endif
 				startbuf, stdoff != 0, startttisstd,
 				startttisgmt);
 			if (usestart) {
@@ -1745,6 +1933,15 @@
 					break;	/* go on to next year */
 				rp = &zp->z_rules[k];
 				rp->r_todo = FALSE;
+#ifdef ICU
+                                if (year >= finalRuleYear && rp == finalRule1) {
+                                    emit_icu_zone(icuFile,
+                                                  zpfirst->z_name, zp->z_gmtoff,
+                                                  rp, finalRuleIndex, year);
+                                    /* only emit this for the first year */
+                                    finalRule1 = NULL;
+                                }
+#endif
 				if (useuntil && ktime >= untiltime)
 					break;
 				stdoff = rp->r_stdoff;
@@ -1773,8 +1970,14 @@
 				doabbr(buf, zp->z_format, rp->r_abbrvar,
 					rp->r_stdoff != 0);
 				offset = oadd(zp->z_gmtoff, rp->r_stdoff);
+#ifdef ICU
+				type = addtype(offset, zp->z_gmtoff, rp->r_stdoff,
+                                        buf, rp->r_stdoff != 0,
+					rp->r_todisstd, rp->r_todisgmt);
+#else
 				type = addtype(offset, buf, rp->r_stdoff != 0,
 					rp->r_todisstd, rp->r_todisgmt);
+#endif
 				addtt(ktime, type);
 			}
 		}
@@ -1788,10 +1991,19 @@
 			if (*startbuf == '\0')
 error(_("can't determine time zone abbreviation to use just after until time"));
 			else	addtt(starttime,
+#ifdef ICU
+					addtype(startoff,
+                                                zp->z_gmtoff, startoff - zp->z_gmtoff,
+                                                startbuf,
+						startoff != zp->z_gmtoff,
+						startttisstd,
+						startttisgmt));
+#else
 					addtype(startoff, startbuf,
 						startoff != zp->z_gmtoff,
 						startttisstd,
 						startttisgmt));
+#endif
 		}
 		/*
 		** Now we may get to set starttime for the next zone line.
@@ -1817,6 +2029,10 @@
 	if (starttime <= min_time ||
 		(timecnt == 1 && attypes[0].at < min_time)) {
 		gmtoffs[0] = gmtoffs[type];
+#ifdef ICU
+		rawoffs[0] = rawoffs[type];
+		dstoffs[0] = dstoffs[type];
+#endif
 		isdsts[0] = isdsts[type];
 		ttisstds[0] = ttisstds[type];
 		ttisgmts[0] = ttisgmts[type];
@@ -1838,8 +2054,15 @@
 }
 
 static int
+#ifdef ICU
+addtype(gmtoff, rawoff, dstoff, abbr, isdst, ttisstd, ttisgmt)
+const long		gmtoff;
+const long		rawoff;
+const long		dstoff;
+#else
 addtype(gmtoff, abbr, isdst, ttisstd, ttisgmt)
 const long		gmtoff;
+#endif
 const char * const	abbr;
 const int		isdst;
 const int		ttisstd;
@@ -1859,12 +2082,25 @@
 		error(_("internal error - addtype called with bad ttisgmt"));
 		exit(EXIT_FAILURE);
 	}
+#ifdef ICU
+	if (isdst != (dstoff != 0)) {
+		error(_("internal error - addtype called with bad isdst/dstoff"));
+		(void) exit(EXIT_FAILURE);
+	}
+        if (gmtoff != (rawoff + dstoff)) {
+		error(_("internal error - addtype called with bad gmt/raw/dstoff"));
+		(void) exit(EXIT_FAILURE);
+        }
+#endif
 	/*
 	** See if there's already an entry for this zone type.
 	** If so, just return its index.
 	*/
 	for (i = 0; i < typecnt; ++i) {
 		if (gmtoff == gmtoffs[i] && isdst == isdsts[i] &&
+#ifdef ICU
+                        rawoff == rawoffs[i] && dstoff == dstoffs[i] &&
+#endif
 			strcmp(abbr, &chars[abbrinds[i]]) == 0 &&
 			ttisstd == ttisstds[i] &&
 			ttisgmt == ttisgmts[i])
@@ -1879,6 +2115,10 @@
 		exit(EXIT_FAILURE);
 	}
 	gmtoffs[i] = gmtoff;
+#ifdef ICU
+        rawoffs[i] = rawoff;
+        dstoffs[i] = dstoff;
+#endif
 	isdsts[i] = isdst;
 	ttisstds[i] = ttisstd;
 	ttisgmts[i] = ttisgmt;