[aat] Start implementing Apple AAT morx table
diff --git a/src/hb-ot-layout-private.hh b/src/hb-ot-layout-private.hh
index be5695d..39d1a67 100644
--- a/src/hb-ot-layout-private.hh
+++ b/src/hb-ot-layout-private.hh
@@ -130,6 +130,10 @@
   struct avar;
 }
 
+namespace AAT {
+  struct morx;
+}
+
 struct hb_ot_layout_lookup_accelerator_t
 {
   template <typename TLookup>
@@ -165,6 +169,7 @@
   OT::hb_lazy_table_loader_t<struct OT::MATH> math;
   OT::hb_lazy_table_loader_t<struct OT::fvar> fvar;
   OT::hb_lazy_table_loader_t<struct OT::avar> avar;
+  OT::hb_lazy_table_loader_t<struct AAT::morx> morx;
 
   unsigned int gsub_lookup_count;
   unsigned int gpos_lookup_count;