diff --git a/ext/date/prereq.mk b/ext/date/prereq.mk
index eb71e55e71..cee7685975 100644
--- a/ext/date/prereq.mk
+++ b/ext/date/prereq.mk
@@ -10,3 +10,10 @@ zonetab.h: zonetab.list
 .PHONY: update-zonetab
 update-zonetab:
 	$(RUBY) -C $(srcdir) update-abbr
+
+.PHONY: update-nothing
+update-nothing:
+
+update = nothing
+
+zonetab.list: update-$(update)