[tz] [PROPOSED 1/2] Omit duplicate Link lines in ziguard output

[Paul Eggert]

* ziguard.awk: Later Link lines now comment out earlier ones.
Formerly, we relied on ‘zic’ to ignore the earlier lines, but this
made for more-confusing ziguard output.  This change does not
affect zic’s output.
---
 ziguard.awk | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/ziguard.awk b/ziguard.awk
index 7d6f7c9..6888c27 100644
--- a/ziguard.awk
+++ b/ziguard.awk
@@ -114,15 +114,16 @@ DATAFORM != "main" {
   }
 }
 
-# If a Link line is followed by a Zone line for the same data, comment
+# If a Link line is followed by a Link or Zone line for the same data, comment
 # out the Link line.  This can happen if backzone overrides a Link
-# with a Zone.
-/^Link/ {
-  linkline[$3] = NR
-}
+# with a Zone or a different Link.
 /^Zone/ {
   sub(/^Link/, "#Link", line[linkline[$2]])
 }
+/^Link/ {
+  sub(/^Link/, "#Link", line[linkline[$3]])
+  linkline[$3] = NR
+}
 
 { line[NR] = $0 }
 
-- 
2.27.0