rewrite extern-multiple-copies to rmake

Author: Oneirical

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -17,7 +17,6 @@ run-make/emit-to-stdout/Makefile
 run-make/export-executable-symbols/Makefile
 run-make/extern-flag-disambiguates/Makefile
 run-make/extern-fn-reachable/Makefile
-run-make/extern-multiple-copies/Makefile
 run-make/extern-multiple-copies2/Makefile
 run-make/fmt-write-bloat/Makefile
 run-make/foreign-double-unwind/Makefile

tests/run-make/extern-multiple-copies/Makefile

@@ -0,0 +1,17 @@
+// In this test, the rust library foo1 exists in two different locations, but only one
+// is required by the --extern flag. This test checks that the copy is ignored (as --extern
+// demands fetching only the original instance of foo1) and that no error is emitted, resulting
+// in successful compilation.
+// https://github.com/rust-lang/rust/pull/29961
+
+// FIXME(Oneirical): test-various
+
+use run_make_support::{path, rfs, rust_lib_name, rustc};
+
+fn main() {
+    rustc().input("foo1.rs").run();
+    rustc().input("foo2.rs").run();
+    rfs::create_dir("foo");
+    rfs::copy(rust_lib_name("foo1"), path("foo").join(rust_lib_name("foo1")));
+    rustc().input("bar.rs").extern_("foo1", rust_lib_name("foo1")).library_search_path("foo").run();
+}