Index: /trunk/src/VBox/GuestHost/HGSMI/Makefile.kmk
===================================================================
--- /trunk/src/VBox/GuestHost/HGSMI/Makefile.kmk	(revision 22650)
+++ /trunk/src/VBox/GuestHost/HGSMI/Makefile.kmk	(revision 22651)
@@ -26,4 +26,10 @@
 	HGSMIHostR3Lib
 
+ifndef VBOX_WITH_ADDITION_DRIVERS
+ if1of ($(KBUILD_TARGET), linux l4) # All drivers are optional, can skip HGSMIGuestR0Lib.
+  LIBRARIES := $(filter-out HGSMIGuestR0Lib, $(LIBRARIES))
+ endif
+endif
+
 
 #