Auto merge of #280 - servo:no-proc-macro, r=nox

Custom derive is stable

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Author: bors-servo

markup5ever/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "markup5ever"
-version = "0.3.0"
+version = "0.3.1"
 authors = [ "The html5ever Project Developers" ]
 license = "MIT / Apache-2.0"
 repository = "https://github.com/servo/html5ever"

markup5ever/lib.rs

@@ -7,7 +7,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![cfg_attr(feature = "heap_size", feature(proc_macro))]
 #[cfg(feature = "heap_size")] #[macro_use] extern crate heapsize_derive;
 #[cfg(feature = "heap_size")] extern crate heapsize;
 extern crate string_cache;