rewrite separate-link to rmake.rs

Author: Oneirical

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -203,7 +203,6 @@ run-make/sanitizer-cdylib-link/Makefile
 run-make/sanitizer-dylib-link/Makefile
 run-make/sanitizer-staticlib-link/Makefile
 run-make/separate-link-fail/Makefile
-run-make/separate-link/Makefile
 run-make/sepcomp-cci-copies/Makefile
 run-make/sepcomp-inlining/Makefile
 run-make/sepcomp-separate/Makefile

tests/run-make/separate-link/Makefile

@@ -0,0 +1,14 @@
+// The compiler flags no-link (and by extension, link-only) used to be broken
+// due to changes in encoding/decoding. This was patched, and this test ensures
+// that these flags are not broken again, resulting in successful compilation.
+// See https://github.com/rust-lang/rust/issues/77857
+
+//@ ignore-cross-compile
+
+use run_make_support::{run, rustc};
+
+fn main() {
+    rustc().stdin(b"fn main(){}").arg("-Zno-link").arg("-").run();
+    rustc().arg("-Zlink-only").input("rust_out.rlink").run();
+    run("rust_out");
+}