diff -r 9e1c9dc23c99 -r 1d942423516c src/hotspot/share/runtime/arguments.hpp
--- a/src/hotspot/share/runtime/arguments.hpp	Tue Feb 12 15:31:40 2019 +0100
+++ b/src/hotspot/share/runtime/arguments.hpp	Tue Feb 05 17:40:15 2019 +0100
@@ -663,4 +663,16 @@
   }                                                      \
 } while(0)
 
+// similar to UNSUPPORTED_OPTION but sets flag to NULL
+#define UNSUPPORTED_OPTION_NULL(opt)                     \
+do {                                                     \
+  if (opt) {                                             \
+    if (FLAG_IS_CMDLINE(opt)) {                          \
+      warning("-XX flag " #opt " not supported in this VM"); \
+    }                                                    \
+    FLAG_SET_DEFAULT(opt, NULL);                         \
+  }                                                      \
+} while(0)
+
+
 #endif // SHARE_RUNTIME_ARGUMENTS_HPP