Initial implementation of custom control header.

diff --git a/include/Makefile.in b/include/Makefile.in
index 348382e..0d19a9a 100644
--- a/include/Makefile.in
+++ b/include/Makefile.in
@@ -14,6 +14,7 @@
 	commdlg.h \
 	compobj.h \
 	cpl.h \
+	custcntl.h \
 	d3d.h \
 	d3d8.h \
 	d3d8caps.h \