--- a/make/autoconf/configure.ac	Thu Jan 25 15:18:13 2018 -0800
+++ b/make/autoconf/configure.ac	Mon Jan 29 17:08:12 2018 -0800
@@ -280,6 +280,9 @@
 # This needs to be done after CUSTOM_LATE_HOOK since we can setup custom features.
 HOTSPOT_VALIDATE_JVM_FEATURES
 
+# Did user specify any unknown variables?
+BASIC_CHECK_LEFTOVER_OVERRIDDEN
+
 # We're messing a bit with internal autoconf variables to put the config.status
 # in the output directory instead of the current directory.
 CONFIG_STATUS="$CONFIGURESUPPORT_OUTPUTDIR/config.status"