Make it an error to include non-top-level headers
Users should #include <hb.h> (or hb-ft.h, hb-glib.h, etc), but
never things like hb-shape.h directly. This makes it easier to
refactor headers later on without breaking compatibility.
diff --git a/src/hb-ot-layout.h b/src/hb-ot-layout.h
index 447e35d..430e54c 100644
--- a/src/hb-ot-layout.h
+++ b/src/hb-ot-layout.h
@@ -24,12 +24,14 @@
* Red Hat Author(s): Behdad Esfahbod
*/
+#ifndef HB_OT_H_IN
+#error "Include <hb-ot.h> instead."
+#endif
+
#ifndef HB_OT_LAYOUT_H
#define HB_OT_LAYOUT_H
-#include "hb-common.h"
-#include "hb-buffer.h"
-#include "hb-font.h"
+#include "hb.h"
#include "hb-ot-tag.h"
