another case where one needs to opt-in to feature for accessing std::mem::POST_DROP_USIZE.

Author: pnkfelix

src/libstd/lib.rs

@@ -121,7 +121,7 @@
 #![feature(unboxed_closures)]
 #![feature(unicode)]
 #![feature(unsafe_destructor)]
-#![feature(unsafe_no_drop_flag)]
+#![feature(unsafe_no_drop_flag, filling_drop)]
 #![feature(macro_reexport)]
 #![feature(hash)]
 #![feature(int_uint)]