--- a/make/CopyImportModules.gmk	Tue Feb 05 10:24:39 2019 +0100
+++ b/make/CopyImportModules.gmk	Tue Feb 05 14:57:24 2019 +0100
@@ -38,7 +38,7 @@
 $(eval $(call FillCacheFind, $(LIBS_DIR) $(CMDS_DIR) $(CONF_DIR)))
 
 ifneq ($(LIBS_DIR), )
-  ifeq ($(OPENJDK_TARGET_OS), windows)
+  ifeq ($(call isTargetOs, windows), true)
     TO_BIN_FILTER := %$(SHARED_LIBRARY_SUFFIX) %.diz %.pdb %.map
 
     $(eval $(call SetupCopyFiles, COPY_LIBS_TO_BIN, \