Add run-make-support to x doc

src/bootstrap/src/core/build_steps/doc.rs

@@ -1028,6 +1028,14 @@ tool_doc!(
     is_library = true,
     crates = ["bootstrap"]
 );
+tool_doc!(
+    RunMakeSupport,
+    "run_make_support",
+    "src/tools/run-make-support",
+    rustc_tool = false,
+    is_library = true,
+    crates = ["run_make_support"]
+);
 
 #[derive(Ord, PartialOrd, Debug, Clone, Hash, PartialEq, Eq)]
 pub struct ErrorIndex {

src/bootstrap/src/core/builder.rs

@@ -888,6 +888,7 @@ impl<'a> Builder<'a> {
                 doc::Tidy,
                 doc::Bootstrap,
                 doc::Releases,
+                doc::RunMakeSupport,
             ),
             Kind::Dist => describe!(
                 dist::Docs,