Auto merge of #71059 - Dylan-DPC:rollup-zgu6jmx, r=Dylan-DPC

Rollup of 6 pull requests

Successful merges:

 - #71029 (Partial work on building with Cargo)
 - #71034 (Clean up E0515 explanation)
 - #71041 (Update links of `rustc guide`)
 - #71048 (Normalize source when loading external foreign source into SourceMap)
 - #71053 (Add some basic docs to `sym` and `kw` modules)
 - #71057 (Clean up E0516 explanation)

Failed merges:

r? @ghost

3 files changed, 2 insertions, 5 deletions

diff --git a/src/librustc_interface/Cargo.toml b/src/librustc_interface/Cargo.toml
index c9d81e51641..8ea866d7cab 100644
--- a/src/librustc_interface/Cargo.toml
+++ b/src/librustc_interface/Cargo.toml
@@ -10,6 +10,7 @@ path = "lib.rs"
 doctest = false
 
 [dependencies]
+libc = "0.2"
 log = "0.4"
 rayon = { version = "0.3.0", package = "rustc-rayon" }
 smallvec = { version = "1.0", features = ["union", "may_dangle"] }
diff --git a/src/librustc_interface/lib.rs b/src/librustc_interface/lib.rs
index ba1e2216ca8..0650d090034 100644
--- a/src/librustc_interface/lib.rs
+++ b/src/librustc_interface/lib.rs
@@ -6,9 +6,6 @@
 #![feature(generators)]
 #![recursion_limit = "256"]
 
-#[cfg(unix)]
-extern crate libc;
-
 mod callbacks;
 pub mod interface;
 mod passes;
diff --git a/src/librustc_interface/tests.rs b/src/librustc_interface/tests.rs
index b452ccfe33a..c75f3b279a2 100644
--- a/src/librustc_interface/tests.rs
+++ b/src/librustc_interface/tests.rs
@@ -1,5 +1,3 @@
-extern crate getopts;
-
 use crate::interface::parse_cfgspecs;
 
 use rustc_data_structures::fx::FxHashSet;
@@ -9,6 +7,7 @@ use rustc_session::config::{build_configuration, build_session_options, to_crate
 use rustc_session::config::{rustc_optgroups, ErrorOutputType, ExternLocation, Options, Passes};
 use rustc_session::config::{ExternEntry, LinkerPluginLto, LtoCli, SwitchWithOptPath};
 use rustc_session::config::{Externs, OutputType, OutputTypes, SymbolManglingVersion};
+use rustc_session::getopts;
 use rustc_session::lint::Level;
 use rustc_session::search_paths::SearchPath;
 use rustc_session::{build_session, Session};