Dump and restore the entropy floor structure in check-point files.

src/engine.c

@@ -5238,6 +5238,7 @@ void engine_struct_dump(struct engine *e, FILE *stream) {
 
   phys_const_struct_dump(e->physical_constants, stream);
   hydro_props_struct_dump(e->hydro_properties, stream);
+  entropy_floor_struct_dump(e->entropy_floor, stream);
   gravity_props_struct_dump(e->gravity_properties, stream);
   stars_props_struct_dump(e->stars_properties, stream);
   pm_mesh_struct_dump(e->mesh, stream);
@@ -5310,6 +5311,11 @@ void engine_struct_restore(struct engine *e, FILE *stream) {
   hydro_props_struct_restore(hydro_properties, stream);
   e->hydro_properties = hydro_properties;
 
+  struct entropy_floor_properties *entropy_floor =
+      (struct entropy_floor_properties *)malloc(sizeof(struct entropy_floor_properties));
+  entropy_floor_struct_restore(entropy_floor, stream);
+  e->entropy_floor = entropy_floor;
+
   struct gravity_props *gravity_properties =
       (struct gravity_props *)malloc(sizeof(struct gravity_props));
   gravity_props_struct_restore(gravity_properties, stream);