rewrite redundant-libs to rmake

Author: Oneirical

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -39,7 +39,6 @@ run-make/pgo-gen-lto/Makefile
 run-make/pgo-indirect-call-promotion/Makefile
 run-make/print-calling-conventions/Makefile
 run-make/print-target-list/Makefile
-run-make/redundant-libs/Makefile
 run-make/remap-path-prefix-dwarf/Makefile
 run-make/reproducible-build-2/Makefile
 run-make/reproducible-build/Makefile

tests/run-make/raw-dylib-c/rmake.rs

@@ -25,5 +25,5 @@ fn main() {
         .actual_text("actual", out_driver)
         .normalize(r#"\r"#, "")
         .run();
-    diff().expected_file("output.txt").actual_text("actual", out_raw).run();
+    diff().expected_file("output.txt").actual_text("actual", out_raw).normalize(r#"\r"#, "").run();
 }

tests/run-make/redundant-libs/Makefile

@@ -0,0 +1,34 @@
+// rustc will remove one of the two redundant references to foo below.  Depending
+// on which one gets removed, we'll get a linker error on SOME platforms (like
+// Linux).  On these platforms, when a library is referenced, the linker will
+// only pull in the symbols needed _at that point in time_.  If a later library
+// depends on additional symbols from the library, they will not have been pulled
+// in, and you'll get undefined symbols errors.
+//
+// So in this example, we need to ensure that rustc keeps the _later_ reference
+// to foo, and not the former one.
+
+//@ ignore-cross-compile
+// Reason: the compiled binary is executed
+//@ ignore-windows-msvc
+// Reason: this test links libraries via link.exe, which only accepts the import library
+// for the dynamic library, i.e. `foo.dll.lib`. However, build_native_dynamic_lib only
+// produces `foo.dll` - the dynamic library itself. To make this test work on MSVC, one
+// would need to derive the import library from the dynamic library.
+// See https://stackoverflow.com/questions/9360280/
+
+use run_make_support::{
+    build_native_dynamic_lib, build_native_static_lib, cwd, is_msvc, rfs, run, rustc,
+};
+
+fn main() {
+    build_native_dynamic_lib("foo");
+    build_native_static_lib("bar");
+    build_native_static_lib("baz");
+    rustc()
+        .args(&["-lstatic=bar", "-lfoo", "-lstatic=baz", "-lfoo"])
+        .input("main.rs")
+        .print("link-args")
+        .run();
+    run("main");
+}