Rc: store the pointer to the value, rather than to the allocation

Author: scottmcm

library/alloc/src/lib.rs

@@ -104,10 +104,12 @@
 #![feature(async_closure)]
 #![feature(async_fn_traits)]
 #![feature(async_iterator)]
+#![feature(box_as_ptr)]
 #![feature(box_uninit_write)]
 #![feature(clone_to_uninit)]
 #![feature(coerce_unsized)]
 #![feature(const_align_of_val)]
+#![feature(const_alloc_layout)]
 #![feature(const_box)]
 #![feature(const_eval_select)]
 #![feature(const_heap)]