diff --git a/src/bootstrap/builder/tests.rs b/src/bootstrap/builder/tests.rs
index 4293844fcbf94..111971534ba5e 100644
--- a/src/bootstrap/builder/tests.rs
+++ b/src/bootstrap/builder/tests.rs
@@ -546,9 +546,7 @@ mod dist {
         );
     }
 
-    //FIXME(mark-i-m): reinstate this test when things are fixed...
-    //#[test]
-    #[allow(dead_code)]
+    #[test]
     fn test_docs() {
         // Behavior of `x.py test` doing various documentation tests.
         let mut config = configure(&[], &[]);
diff --git a/src/bootstrap/doc.rs b/src/bootstrap/doc.rs
index b43108ccaf984..96cabf754490b 100644
--- a/src/bootstrap/doc.rs
+++ b/src/bootstrap/doc.rs
@@ -693,6 +693,7 @@ impl Step for UnstableBookGen {
         builder.create_dir(&out);
         builder.remove_dir(&out);
         let mut cmd = builder.tool_cmd(Tool::UnstableBookGen);
+        cmd.arg(builder.src.join("library"));
         cmd.arg(builder.src.join("src"));
         cmd.arg(out);
 
diff --git a/src/bootstrap/test.rs b/src/bootstrap/test.rs
index addc51faa5e29..05af7210b1c68 100644
--- a/src/bootstrap/test.rs
+++ b/src/bootstrap/test.rs
@@ -106,19 +106,18 @@ impl Step for Linkcheck {
     ///
     /// This tool in `src/tools` will verify the validity of all our links in the
     /// documentation to ensure we don't have a bunch of dead ones.
-    fn run(self, _builder: &Builder<'_>) {
-        // FIXME(mark-i-m): uncomment this after we fix the links...
-        // let host = self.host;
+    fn run(self, builder: &Builder<'_>) {
+        let host = self.host;
 
-        // builder.info(&format!("Linkcheck ({})", host));
+        builder.info(&format!("Linkcheck ({})", host));
 
-        // builder.default_doc(None);
+        builder.default_doc(None);
 
-        // let _time = util::timeit(&builder);
-        // try_run(
-        //     builder,
-        //     builder.tool_cmd(Tool::Linkchecker).arg(builder.out.join(host.triple).join("doc")),
-        // );
+        let _time = util::timeit(&builder);
+        try_run(
+            builder,
+            builder.tool_cmd(Tool::Linkchecker).arg(builder.out.join(host.triple).join("doc")),
+        );
     }
 
     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
diff --git a/src/tools/unstable-book-gen/src/main.rs b/src/tools/unstable-book-gen/src/main.rs
index aa24881ac6bd7..11617911446ec 100644
--- a/src/tools/unstable-book-gen/src/main.rs
+++ b/src/tools/unstable-book-gen/src/main.rs
@@ -94,13 +94,15 @@ fn copy_recursive(from: &Path, to: &Path) {
 }
 
 fn main() {
-    let src_path_str = env::args_os().skip(1).next().expect("source path required");
-    let dest_path_str = env::args_os().skip(2).next().expect("destination path required");
+    let library_path_str = env::args_os().skip(1).next().expect("library path required");
+    let src_path_str = env::args_os().skip(2).next().expect("source path required");
+    let dest_path_str = env::args_os().skip(3).next().expect("destination path required");
+    let library_path = Path::new(&library_path_str);
     let src_path = Path::new(&src_path_str);
     let dest_path = Path::new(&dest_path_str);
 
     let lang_features = collect_lang_features(src_path, &mut false);
-    let lib_features = collect_lib_features(src_path)
+    let lib_features = collect_lib_features(library_path)
         .into_iter()
         .filter(|&(ref name, _)| !lang_features.contains_key(name))
         .collect();