Auto merge of #128102 - Oneirical:real-testate, r=Kobzol

Migrate `extern-diff-internal-name`, `extern-multiple-copies` and `extern-multiple-copies2` `run-make` tests to rmake

Part of #121876 and the associated [Google Summer of Code project](https://blog.rust-lang.org/2024/05/01/gsoc-2024-selected-projects.html).

Please try:

try-job: test-various

Author: bors

Diff for: src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -13,11 +13,8 @@ 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
-run-make/extern-multiple-copies2/Makefile
 run-make/fmt-write-bloat/Makefile
 run-make/foreign-double-unwind/Makefile
 run-make/foreign-exceptions/Makefile

Diff for: tests/run-make/extern-diff-internal-name/Makefile

@@ -0,0 +1,15 @@
+// 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
+
+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();
+}

Diff for: tests/run-make/extern-diff-internal-name/rmake.rs

@@ -0,0 +1,15 @@
+// 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
+
+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();
+}

Diff for: tests/run-make/extern-multiple-copies/Makefile

@@ -0,0 +1,22 @@
+// Almost identical to `extern-multiple-copies`, but with a variation in the --extern calls
+// and the addition of #[macro_use] in the rust code files, which used to break --extern
+// until #33625.
+// 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/issues/33762
+
+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", path("foo").join(rust_lib_name("foo1")))
+        .extern_("foo2", rust_lib_name("foo2"))
+        .run();
+}