Migrate run-make/doctests-runtool to rmake

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -44,7 +44,6 @@ run-make/dep-graph/Makefile
 run-make/dep-info-doesnt-run-much/Makefile
 run-make/dep-info-spaces/Makefile
 run-make/dep-info/Makefile
-run-make/doctests-runtool/Makefile
 run-make/dump-ice-to-disk/Makefile
 run-make/dump-mono-stats/Makefile
 run-make/duplicate-output-flavors/Makefile

tests/run-make/doctests-runtool/rmake.rs

@@ -0,0 +1,39 @@
+// Tests behavior of rustdoc `--runtool`.
+
+use run_make_support::{rustc, rustdoc, tmp_dir};
+use std::env::current_dir;
+use std::fs::{create_dir, remove_dir_all};
+use std::path::PathBuf;
+
+fn mkdir(name: &str) -> PathBuf {
+    let dir = tmp_dir().join(name);
+    create_dir(&dir).expect("failed to create doctests folder");
+    dir
+}
+
+// Behavior with --runtool with relative paths and --test-run-directory.
+fn main() {
+    let run_dir_name = "rundir";
+    let run_dir = mkdir(run_dir_name);
+    let run_tool = mkdir("runtool");
+    let run_tool_binary = run_tool.join("runtool");
+
+    rustc().input("t.rs").crate_type("rlib").run();
+    rustc().input("runtool.rs").arg("-o").arg(&run_tool_binary).run();
+
+    rustdoc()
+        .input(current_dir().unwrap().join("t.rs"))
+        .arg("-Zunstable-options")
+        .arg("--test")
+        .arg("--test-run-directory")
+        .arg(run_dir_name)
+        .arg("--runtool")
+        .arg(&run_tool_binary)
+        .arg("--extern")
+        .arg("t=libt.rlib")
+        .current_dir(tmp_dir())
+        .run();
+
+    remove_dir_all(run_dir);
+    remove_dir_all(run_tool);
+}