Build rustdoc on-demand.

Rustdoc is no longer compiled in every stage, alongside rustc, instead
it is only compiled when requested, and generally only for the last
stage.

src/rustc/Cargo.toml

@@ -7,16 +7,11 @@ version = "0.0.0"
 name = "rustc"
 path = "rustc.rs"
 
-[[bin]]
-name = "rustdoc"
-path = "rustdoc.rs"
-
 # All optional dependencies so the features passed to this Cargo.toml select
 # what should actually be built.
 [dependencies]
 rustc_back = { path = "../librustc_back" }
 rustc_driver = { path = "../librustc_driver" }
-rustdoc = { path = "../librustdoc" }
 
 [features]
 jemalloc = ["rustc_back/jemalloc"]

src/rustc/rustdoc.rs

@@ -1,15 +0,0 @@
-// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
-// file at the top-level directory of this distribution and at
-// http://rust-lang.org/COPYRIGHT.
-//
-// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
-// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
-// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
-// option. This file may not be copied, modified, or distributed
-// except according to those terms.
-
-#![feature(rustc_private)]
-
-extern crate rustdoc;
-
-fn main() { rustdoc::main() }