--- a/make/Main.gmk	Mon Dec 03 23:58:15 2018 +0800
+++ b/make/Main.gmk	Mon Dec 03 18:43:24 2018 +0100
@@ -643,6 +643,7 @@
   # Declare dependencies between hotspot-<variant>* targets
   $(foreach v, $(JVM_VARIANTS), \
       $(eval hotspot-$v: hotspot-$v-gensrc hotspot-$v-libs) \
+      $(eval hotspot-$v-gensrc: java.base-copy) \
       $(eval hotspot-$v-libs: hotspot-$v-gensrc java.base-copy) \
   )