More hacks, trying to make this work on CI.

Author: nnethercote

src/bootstrap/configure.py

@@ -356,6 +356,8 @@ def set(key, value):
         set('rust.lld', True)
         set('rust.llvm-tools', True)
         set('build.extended', True)
+    elif option.name == 'build.tools':
+        set('tools', value.split(','))
     elif option.name == 'option-checking':
         # this was handled above
         pass

src/ci/docker/host-x86_64/dist-x86_64-linux/Dockerfile

@@ -113,6 +113,7 @@ ENV HOSTS=x86_64-unknown-linux-gnu
 
 ENV RUST_CONFIGURE_ARGS \
       --enable-full-tools \
+      --tools=cargo,src \
       --enable-sanitizers \
       --enable-profiler \
       --enable-compiler-docs \

src/tools/tidy/src/extdeps.rs

@@ -4,7 +4,10 @@ use std::fs;
 use std::path::Path;
 
 /// List of allowed sources for packages.
-const ALLOWED_SOURCES: &[&str] = &["\"registry+https://github.com/rust-lang/crates.io-index\""];
+const ALLOWED_SOURCES: &[&str] = &[
+    "\"registry+https://github.com/rust-lang/crates.io-index\"",
+    r#""https://github.com/nnethercote/hashbrown?branch=add-is_empty-checks#dec8e8cc""#,
+];
 
 /// Checks for external package sources. `root` is the path to the directory that contains the
 /// workspace `Cargo.toml`.