rewrite std-core-cycle to rmake

Author: Oneirical

src/tools/tidy/src/allowed_run_make_makefiles.txt

@@ -171,7 +171,6 @@ run-make/static-dylib-by-default/Makefile
 run-make/static-extern-type/Makefile
 run-make/staticlib-blank-lib/Makefile
 run-make/staticlib-dylib-linkage/Makefile
-run-make/std-core-cycle/Makefile
 run-make/symbol-mangling-hashed/Makefile
 run-make/symbol-visibility/Makefile
 run-make/symbols-include-type-name/Makefile

tests/run-make/std-core-cycle/Makefile

@@ -0,0 +1,28 @@
+// In some cases, linking libraries with GNU used to fail due to how
+// `std` and `core` possess a circular dependency with one another, and
+// how the linker could not go back through its symbol processing to resolve
+// the circular link. #49316 fixed this, and this test reproduces a minimal
+// version of one such linking attempt which used to fail.
+// See https://github.com/rust-lang/rust/issues/18807
+
+//@ ignore-cross-compile
+
+use run_make_support::{is_darwin, is_windows, rustc};
+
+fn main() {
+    rustc().input("bar.rs").run();
+
+    let mut rustc_foo = rustc();
+    rustc_foo.input("foo.rs");
+    let mut rustc_foo_panic = rustc();
+    rustc_foo_panic.input("foo.rs").panic("abort");
+
+    if !is_darwin() && !is_windows() {
+        rustc_foo.arg("-Clink-args=-Wl,--no-undefined");
+        rustc_foo_panic.arg("-Clink-args=-Wl,--no-undefined");
+    }
+
+    rustc_foo.run();
+    rustc_foo_panic.run();
+}
+