ddk: Add a stub ntddk.h header.

include/Makefile.in

diff --git a/include/Makefile.in b/include/Makefile.in
index 73d1cb0..287cfa9 100644
--- a/include/Makefile.in
+++ b/include/Makefile.in
@@ -135,6 +135,7 @@
 	ddk/imm.h \
 	ddk/mountmgr.h \
 	ddk/ntddcdvd.h \
+	ddk/ntddk.h \
 	ddk/ntddser.h \
 	ddk/ntddtape.h \
 	ddk/wdm.h \