Index: /trunk/src/VBox/Additions/linux/Makefile.kmk
===================================================================
--- /trunk/src/VBox/Additions/linux/Makefile.kmk	(revision 66025)
+++ /trunk/src/VBox/Additions/linux/Makefile.kmk	(revision 66026)
@@ -34,15 +34,15 @@
 ifdef VBOX_WITH_TESTCASES
  ifndef VBOX_ONLY_SDK
-  VBOX_LNX_ADD_TEST=$(PATH_TARGET)/tstguest_mod
-  VBOX_LNX_ADD_TEST_TARGET=$(PATH_TARGET)/tstguest_mod.run
-  VBOX_LNX_ADD_SOURCES=$(vboxguest-src_2_INST_TARGETS) $(vboxsf-mod_2_INST_TARGETS) $(vboxvideo_drm-mod_2_INST_TARGETS)
-  TESTING += $(VBOX_LNX_ADD_TEST_TARGET)
-  OTHERS += $(VBOX_LNX_ADD_TEST_TARGET)
+  VBOX_LNX_ADD_TEST        = $(PATH_TARGET)/tstguest_mod
+  VBOX_LNX_ADD_TEST_TARGET = $(PATH_TARGET)/tstguest_mod.run
+  TESTING     += $(VBOX_LNX_ADD_TEST_TARGET)
+  OTHERS      += $(VBOX_LNX_ADD_TEST_TARGET)
   OTHER_CLEAN += $(VBOX_LNX_ADD_TEST)
-$$(VBOX_LNX_ADD_TEST_TARGET): $$(VBOX_LNX_ADD_SOURCES)
+ $$(VBOX_LNX_ADD_TEST_TARGET): $$(vboxguest-src_2_INST_TARGETS) $$(vboxsf-mod_2_INST_TARGETS) $$(vboxvideo_drm-mod_2_INST_TARGETS)
 	$(QUIET)$(call MSG_L1,Doing a test build of the guest kernel modules)
-	$(QUIET)$(ASH) -c "rm -f $@"
-	$(QUIET)$(ASH) -c "mkdir -p $(VBOX_LNX_ADD_TEST) && cp -r $(PATH_STAGE_BIN)/additions/src/* $(VBOX_LNX_ADD_TEST)"
-	$(QUIET)$(ASH) -c "cd $(VBOX_LNX_ADD_TEST) && make"
+	$(QUIET)$(RM) -f -- "$@"
+	$(QUIET)$(MKDIR) -p -- "$(VBOX_LNX_ADD_TEST)"
+	$(QUIET)$(CP) -R --changed -- $(PATH_STAGE_BIN)/additions/src/* "$(VBOX_LNX_ADD_TEST)"
+	+ $(QUIET)make -C $(VBOX_LNX_ADD_TEST)
 	$(QUIET)$(APPEND) -t "$@" "done"
  endif