Update tzdata and zoneinfo to version 2020f.

Author: GitHub Actions

tzdata/Makefile

@@ -945,7 +945,10 @@ check_public: $(VERSION_DEPS)
 		mkdir public.dir
 		ln $(VERSION_DEPS) public.dir
 		cd public.dir && $(MAKE) CFLAGS='$(GCC_DEBUG_FLAGS)' ALL
-		for i in $(TDATA_TO_CHECK) public.dir/tzdata.zi; do \
+		for i in $(TDATA_TO_CHECK) public.dir/tzdata.zi \
+		    public.dir/vanguard.zi public.dir/main.zi \
+		    public.dir/rearguard.zi; \
+		do \
 		  public.dir/zic -v -d public.dir/zoneinfo $$i 2>&1 || exit; \
 		done
 		public.dir/zic -v -d public.dir/zoneinfo-all $(TDATA_TO_CHECK)

tzdata/NEWS

@@ -1,5 +1,13 @@
 News for the tz database
 
+Release 2020f - 2020-12-29 00:17:46 -0800
+
+  Change to build procedure
+
+    'make rearguard_tarballs' no longer generates a bad rearguard.zi,
+    fixing a 2020e bug.  (Problem reported by Deborah Goldsmith.)
+
+
 Release 2020e - 2020-12-22 15:14:34 -0800
 
   Briefly:

tzdata/version

@@ -1 +1 @@
-2020e
+2020f

tzdata/ziguard.awk

@@ -37,7 +37,7 @@ DATAFORM != "main" {
 
   # If this line should differ due to Czechoslovakia using negative SAVE values,
   # uncomment the desired version and comment out the undesired one.
-  if (zone == "Europe/Prague" && /1947 Feb 23/) {
+  if (zone == "Europe/Prague" && /^#?[\t ]+[01]:00[\t ]/ && /1947 Feb 23/) {
     if (($(in_comment + 2) != "-") == vanguard) {
       uncomment = in_comment
     } else {
@@ -65,10 +65,11 @@ DATAFORM != "main" {
   # uncomment the desired version and comment out the undesired one.
   Rule_Namibia = /^#?Rule[\t ]+Namibia[\t ]/
   Zone_using_Namibia_rule \
-    = (zone == "Africa/Windhoek" \
+    = (zone == "Africa/Windhoek" && /^#?[\t ]+[12]:00[\t ]/ \
        && ($(in_comment + 2) == "Namibia" \
-	   || (1994 <= $(in_comment + 4) && $(in_comment + 4) <= 2017) \
-	   || in_comment + 3 == NF))
+	   || ($(in_comment + 2) == "-" && $(in_comment + 3) == "CAT" \
+	       && ((1994 <= $(in_comment + 4) && $(in_comment + 4) <= 2017) \
+		   || in_comment + 3 == NF))))
   if (Rule_Namibia || Zone_using_Namibia_rule) {
       if ((Rule_Namibia \
 	   ? ($(in_comment + 9) ~ /^-/ \