link the cargo book into the bookshelf

src/bootstrap/doc.rs

@@ -136,7 +136,6 @@ impl Step for UnstableBook {
 pub struct CargoBook {
     target: Interned<String>,
     name: Interned<String>,
-    src: Interned<PathBuf>,
 }
 
 impl Step for CargoBook {
@@ -152,21 +151,25 @@ impl Step for CargoBook {
         run.builder.ensure(CargoBook {
             target: run.target,
             name: INTERNER.intern_str("cargo"),
-            src: INTERNER.intern_path(PathBuf::from("src/tools/cargo/src/doc/book")),
         });
     }
 
     fn run(self, builder: &Builder) {
         let build = builder.build;
+
         let target = self.target;
         let name = self.name;
-        let src = self.src;
+        let src = PathBuf::from("src/tools/cargo/src/doc/book");
+
         let out = build.doc_out(target);
         t!(fs::create_dir_all(&out));
 
         let out = out.join(name);
+
         println!("Cargo Book ({}) - {}", target, name);
+
         let _ = fs::remove_dir_all(&out);
+
         build.run(builder.tool_cmd(Tool::Rustbook)
                        .arg("build")
                        .arg(&src)

src/doc/index.md

@@ -28,6 +28,7 @@ Rust provides a number of book-length sets of documentation, collectively
 nicknamed 'The Rust Bookshelf.'
 
 * [The Rust Programming Language][book] teaches you how to program in Rust.
+* [The Cargo Book][cargo-book] is a guide to Cargo, Rust's build tool and dependency manager.
 * [The Unstable Book][unstable-book] has documentation for unstable features.
 * [The Rustonomicon][nomicon] is your guidebook to the dark arts of unsafe Rust.
 * [The Reference][ref] is not a formal spec, but is more detailed and comprehensive than the book.
@@ -53,4 +54,5 @@ before this policy was put into place. That work is being tracked
 [nomicon]: nomicon/index.html
 [unstable-book]: unstable-book/index.html
 [rustdoc-book]: rustdoc/index.html
+[cargo-book]: cargo/index.html