rewrite extern-diff-internal-name to rmake

Author: Oneirical

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -15,7 +15,6 @@ run-make/dep-info/Makefile
 run-make/dump-ice-to-disk/Makefile
 run-make/emit-to-stdout/Makefile
 run-make/export-executable-symbols/Makefile
-run-make/extern-diff-internal-name/Makefile
 run-make/extern-flag-disambiguates/Makefile
 run-make/extern-fn-reachable/Makefile
 run-make/extern-multiple-copies/Makefile

tests/run-make/extern-diff-internal-name/Makefile

@@ -0,0 +1,17 @@
+// In the following scenario:
+// 1. The crate foo, is referenced multiple times
+// 2. --extern foo=./path/to/libbar.rlib is specified to rustc
+// 3. The internal crate name of libbar.rlib is not foo
+// Compilation fails with the "multiple crate versions" error message.
+// As this was fixed in #17189, this regression test ensures this bug does not
+// make a resurgence.
+// See https://github.com/rust-lang/rust/pull/17189
+
+//FIXME(Oneirical): test-various
+
+use run_make_support::{rust_lib_name, rustc};
+
+fn main() {
+    rustc().input("lib.rs").run();
+    rustc().input("test.rs").extern_("foo", rust_lib_name("bar")).run();
+}