--- old/make/lib/Lib-java.base.gmk	2018-08-29 10:17:55.425661656 -0700
+++ new/make/lib/Lib-java.base.gmk	2018-08-29 10:17:55.029653681 -0700
@@ -204,3 +204,14 @@
 
   TARGETS += $(JAVA_BASE_EXPORT_SYMBOL_FILE)
 endif
+
+################################################################################
+# Copy tzmappings file for Windows
+
+ifeq ($(OPENJDK_TARGET_OS), windows)
+  $(eval $(call SetupCopyFiles, COPY_TZMAPPINGS, \
+      FILES := $(SUPPORT_OUTPUTDIR)/gensrc/java.base/windows/conf/tzmappings, \
+      DEST := $(call FindLibDirForModule, $(MODULE)), \
+  ))
+  TARGETS += $(COPY_TZMAPPINGS)
+endif