Index: /trunk/Config.kmk
===================================================================
--- /trunk/Config.kmk	(revision 49915)
+++ /trunk/Config.kmk	(revision 49916)
@@ -1874,5 +1874,5 @@
 # The Microsoft IDL compiler (the SDK build needs this on non-Windows).
 VBOX_WIN_MIDL ?= $(EXEC_X86_WIN32) $(call VBOX_FN_MAKE_WIN_PATH,$(firstword $(wildcard $(addsuffix /[Mm][Ii][Dd][Ll].[Ee][Xx][Ee], \
-	$(PATH_DEVTOOLS)/win.x86/sdk/v7.1/Bin$(if-expr "$(KBUILD_HOST_ARCH)" == "amd64",/x64,) \
+	$(PATH_DEVTOOLS)/win.x86/sdk/v7.1/Bin$(if-expr "$(KBUILD_HOST).$(KBUILD_HOST_ARCH)" == "win.amd64",/x64,) \
 	$(PATH_DEVTOOLS)/win.x86/ddk/7600.16385.1/bin/x86 \
 	$(PATH_DEVTOOLS)/win.x86/bin \