Index: /trunk/src/VBox/Main/Makefile.kmk
===================================================================
--- /trunk/src/VBox/Main/Makefile.kmk	(revision 48326)
+++ /trunk/src/VBox/Main/Makefile.kmk	(revision 48327)
@@ -920,5 +920,6 @@
 + $(VBoxCOM_0_OUTDIR)/VirtualBox.h \
 + $(VBoxCOM_0_OUTDIR)/VirtualBox.tlb: $(VBOX_IDL_FILE.MSCOM) | $$(dir $$@)
-	$(VBOX_WIN_MIDL) /nologo $(if-expr "$(KBUILD_TARGET_ARCH)" == "amd64",/env amd64,/env win32) /target NT51 \
+	$(VBOX_WIN_MIDL) /nologo \
+		$(if-expr "$(KBUILD_TARGET_ARCH)" == "amd64" && "$(KBUILD_HOST)" == "win",/env amd64,/env win32) /target NT51 \
 		/out $(call VBOX_FN_MAKE_WIN_PATH,$(VBoxCOM_0_OUTDIR)) \
 		/cpp_cmd $(subst $(EXEC_X86_WIN32),,$(call VBOX_FN_MAKE_WIN_PATH,$(TOOL_$(VBOX_VCC_TOOL)_CC))) \