diff -urN VirtualBox-6.0.6/src/VBox/HostDrivers/VBoxNetAdp/Makefile.kmk VirtualBox-6.0.6.new/src/VBox/HostDrivers/VBoxNetAdp/Makefile.kmk
--- VirtualBox-6.0.6/src/VBox/HostDrivers/VBoxNetAdp/Makefile.kmk	2019-04-16 12:16:38.000000000 +0200
+++ VirtualBox-6.0.6.new/src/VBox/HostDrivers/VBoxNetAdp/Makefile.kmk	2019-05-04 15:19:14.545497602 +0200
@@ -175,7 +175,7 @@
 		| $$(dir $$@)
 	$(QUIET)$(RM) -f -- $@
  ifndef VBOX_WITH_HARDENING
-	$(QUIET)$(SED) -e "s;-DVBOX_WITH_HARDENING;;g" --output $@ $<
+	$(QUIET)$(SED) -e "s;VBOX_WITH_HARDENING;;g" --output $@ $<
  else
 	$(QUIET)$(CP) -f $< $@
  endif
diff -urN VirtualBox-6.0.6/src/VBox/HostDrivers/VBoxNetFlt/Makefile.kmk VirtualBox-6.0.6.new/src/VBox/HostDrivers/VBoxNetFlt/Makefile.kmk
--- VirtualBox-6.0.6/src/VBox/HostDrivers/VBoxNetFlt/Makefile.kmk	2019-04-16 12:16:39.000000000 +0200
+++ VirtualBox-6.0.6.new/src/VBox/HostDrivers/VBoxNetFlt/Makefile.kmk	2019-05-04 15:19:13.809493324 +0200
@@ -525,7 +525,7 @@
 		| $$(dir $$@)
 	$(QUIET)$(RM) -f -- $@
  ifndef VBOX_WITH_HARDENING
-	$(QUIET)$(SED) -e "s;-DVBOX_WITH_HARDENING;;g" --output $@ $<
+	$(QUIET)$(SED) -e "s;VBOX_WITH_HARDENING;;g" --output $@ $<
  else
 	$(QUIET)$(CP) -f $< $@
  endif
diff -urN VirtualBox-6.0.6/src/VBox/HostDrivers/VBoxPci/Makefile.kmk VirtualBox-6.0.6.new/src/VBox/HostDrivers/VBoxPci/Makefile.kmk
--- VirtualBox-6.0.6/src/VBox/HostDrivers/VBoxPci/Makefile.kmk	2019-04-16 12:16:40.000000000 +0200
+++ VirtualBox-6.0.6.new/src/VBox/HostDrivers/VBoxPci/Makefile.kmk	2019-05-04 15:42:12.029664987 +0200
@@ -67,7 +67,7 @@
 		| $$(dir $$@)
 	$(QUIET)$(RM) -f -- $@
  ifndef VBOX_WITH_HARDENING
-	$(QUIET)$(SED) -e "s;-DVBOX_WITH_HARDENING;;g" --output $@ $<
+	$(QUIET)$(SED) -e "s;VBOX_WITH_HARDENING;;g" --output $@ $<
  else
 	$(QUIET)$(CP) -f $< $@
  endif