copy retain_gids from input to plan

src/hb-subset-plan.cc

@@ -204,6 +204,7 @@ hb_subset_plan_create (hb_face_t           *face,
   plan->drop_hints = input->drop_hints;
   plan->drop_layout = input->drop_layout;
   plan->desubroutinize = input->desubroutinize;
+  plan->retain_gids = input->retain_gids;
   plan->unicodes = hb_set_create();
   plan->source = hb_face_reference (face);
   plan->dest = hb_face_builder_create ();

src/hb-subset-plan.hh

@@ -42,6 +42,7 @@ struct hb_subset_plan_t
   bool drop_hints : 1;
   bool drop_layout : 1;
   bool desubroutinize : 1;
+  bool retain_gids : 1;
 
   // For each cp that we'd like to retain maps to the corresponding gid.
   hb_set_t *unicodes;