Description: Fix links to cargo-doc
 We package cargo docs in a slightly different location; also tweak linkchecker
 to not fail these links.

--- a/src/tools/linkchecker/main.rs
+++ b/src/tools/linkchecker/main.rs
@@ -19,6 +19,7 @@
 use std::collections::hash_map::Entry;
 use std::collections::{HashMap, HashSet};
 use std::env;
+use std::ffi::OsStr;
 use std::fs;
 use std::path::{Component, Path, PathBuf};
 use std::rc::Rc;
@@ -331,7 +332,15 @@
             print!("{}:{}: broken link - ", path.display(), i + 1);
             println!("{}", path.display());
         } else {
-            let pretty_path = path.strip_prefix(root).unwrap_or(&path);
+            let pretty_path = match path.strip_prefix(root) {
+                Ok(suf) => suf,
+                Err(_) => if path.components().any(|x| x == Component::Normal(OsStr::new("cargo-doc"))) {
+                    // link to cargo-doc, ok for our Debian build
+                    return;
+                } else {
+                    &path
+                }
+            };
             if !is_exception(file, pretty_path.to_str().unwrap()) {
                 *errors = true;
                 print!("{}:{}: broken link - ", pretty_file.display(), i + 1);
--- a/src/doc/index.md
+++ b/src/doc/index.md
@@ -87,7 +87,7 @@
 
 ## The Cargo Book
 
-[The Cargo Book](cargo/index.html) is a guide to Cargo, Rust's build tool and dependency manager.
+[The Cargo Book](../../cargo-doc/doc/index.html) is a guide to Cargo, Rust's build tool and dependency manager.
 
 ## The Rustdoc Book
 
--- a/src/doc/reference/src/conditional-compilation.md
+++ b/src/doc/reference/src/conditional-compilation.md
@@ -332,6 +332,6 @@
 [`target_feature` attribute]: attributes/codegen.md#the-target_feature-attribute
 [attribute]: attributes.md
 [attributes]: attributes.md
-[cargo-feature]: ../cargo/reference/features.html
+[cargo-feature]: ../../cargo-doc/doc/reference/features.html
 [crate type]: linkage.md
 [static C runtime]: linkage.md#static-and-dynamic-c-runtimes
--- a/src/doc/reference/src/introduction.md
+++ b/src/doc/reference/src/introduction.md
@@ -133,8 +133,8 @@
 [the Rust Reference repository]: https://github.com/rust-lang/reference/
 [Unstable Book]: https://doc.rust-lang.org/nightly/unstable-book/
 [_Expression_]: expressions.md
-[cargo book]: ../cargo/index.html
-[cargo reference]: ../cargo/reference/index.html
+[cargo book]: ../../cargo-doc/doc/index.html
+[cargo reference]: ../../cargo-doc/doc/reference/index.html
 [expressions chapter]: expressions.html
 [file an issue]: https://github.com/rust-lang/reference/issues
 [lifetime of temporaries]: expressions.html#temporaries
--- a/src/doc/reference/src/linkage.md
+++ b/src/doc/reference/src/linkage.md
@@ -200,7 +200,7 @@
 }
 ```
 
-[cargo]: ../cargo/reference/environment-variables.html#environment-variables-cargo-sets-for-build-scripts
+[cargo]: ../../cargo-doc/doc/reference/environment-variables.html#environment-variables-cargo-sets-for-build-scripts
 
 To use this feature locally, you typically will use the `RUSTFLAGS` environment
 variable to specify flags to the compiler through Cargo. For example to compile
--- a/src/doc/reference/src/procedural-macros.md
+++ b/src/doc/reference/src/procedural-macros.md
@@ -272,7 +272,7 @@
 ```
 
 [Attribute macros]: #attribute-macros
-[Cargo's build scripts]: ../cargo/reference/build-scripts.html
+[Cargo's build scripts]: ../../cargo-doc/doc/reference/build-scripts.html
 [Derive macros]: #derive-macros
 [Function-like macros]: #function-like-procedural-macros
 [`TokenStream`]: ../proc_macro/struct.TokenStream.html
--- a/src/doc/rustc/src/tests/index.md
+++ b/src/doc/rustc/src/tests/index.md
@@ -266,7 +266,7 @@
 [`--test` option]: ../command-line-arguments.md#option-test
 [`-Z panic-abort-tests`]: https://github.com/rust-lang/rust/issues/67650
 [`available_concurrency`]: ../../std/thread/fn.available_concurrency.html
-[`cargo test`]: ../../cargo/commands/cargo-test.html
+[`cargo test`]: ../../../cargo-doc/doc/commands/cargo-test.html
 [`libtest`]: ../../test/index.html
 [`main` function]: ../../reference/crates-and-source-files.html#main-functions
 [`Result`]: ../../std/result/index.html
@@ -275,7 +275,7 @@
 [attribute-should_panic]: ../../reference/attributes/testing.html#the-should_panic-attribute
 [attribute-test]: ../../reference/attributes/testing.html#the-test-attribute
 [bench-docs]: ../../unstable-book/library-features/test.html
-[Cargo]: ../../cargo/index.html
+[Cargo]: ../../../cargo-doc/doc/index.html
 [crate type]: ../../reference/linkage.html
 [custom_test_frameworks documentation]: ../../unstable-book/language-features/custom-test-frameworks.html
 [nightly channel]: ../../book/appendix-07-nightly-rust.html
--- a/src/doc/rustc/src/what-is-rustc.md
+++ b/src/doc/rustc/src/what-is-rustc.md
@@ -5,7 +5,7 @@
 produce binary code, either as a library or executable.
 
 Most Rust programmers don't invoke `rustc` directly, but instead do it through
-[Cargo](../cargo/index.html). It's all in service of `rustc` though! If you
+[Cargo](../../cargo-doc/doc/index.html). It's all in service of `rustc` though! If you
 want to see how Cargo calls `rustc`, you can
 
 ```bash