diff --git a/include/Makefile.in b/include/Makefile.in
index 702a660..4b39082 100644
--- a/include/Makefile.in
+++ b/include/Makefile.in
@@ -195,6 +195,7 @@
 	winsock2.h \
 	winspool.h \
 	winsvc.h \
+	winternl.h \
 	winuser.h \
 	winver.h \
 	wnaspi32.h \