acledit: Add wfext.h.

include/Makefile.in

diff --git a/include/Makefile.in b/include/Makefile.in
index d2ceb15..3b08d73 100644
--- a/include/Makefile.in
+++ b/include/Makefile.in
@@ -369,6 +369,7 @@
 	ver.h \
 	vfw.h \
 	vfwmsgs.h \
+	wfext.h \
 	winbase.h \
 	wincon.h \
 	wincred.h \