Auto merge of #126111 - Zalathar:fulldeps-hotplug, r=jieyouxu

Port `tests/run-make-fulldeps/hotplug_codegen_backend` to ui-fulldeps

This is the last remaining run-make-fulldeps test, which means I actually had to leave behind a dummy README file to prevent compiletest from complaining about a missing directory.

(Removing the run-make-fulldeps suite entirely is non-trivial, so I intend to do so in a separate PR after this one.)

---

I wasn't sure about adding a new kind of aux build just for this one test, so I also tried to just port this test from Makefile to [rmake](https://github.com/rust-lang/rust/issues/121876) instead.

But I found that I couldn't get rmake to fully work for a run-make-fulldeps test, which convinced me that getting rid of run-make-fulldeps is worthwhile.

r? `@jieyouxu`

1 files changed, 3 insertions, 2 deletions

diff --git a/src/doc/unstable-book/src/compiler-flags/codegen-backend.md b/src/doc/unstable-book/src/compiler-flags/codegen-backend.md
index 67634be6993..7e4be9841f4 100644
--- a/src/doc/unstable-book/src/compiler-flags/codegen-backend.md
+++ b/src/doc/unstable-book/src/compiler-flags/codegen-backend.md
@@ -12,8 +12,9 @@ backend. The library must be of crate type `dylib` and must contain a function
 named `__rustc_codegen_backend` with a signature of `fn() -> Box<dyn rustc_codegen_ssa::traits::CodegenBackend>`.
 
 ## Example
-See also the [`hotplug_codegen_backend`](https://github.com/rust-lang/rust/tree/master/tests/run-make-fulldeps/hotplug_codegen_backend) test
-for a full example.
+See also the [`codegen-backend/hotplug`] test for a working example.
+
+[`codegen-backend/hotplug`]: https://github.com/rust-lang/rust/tree/master/tests/ui-fulldeps/codegen-backend/hotplug.rs
 
 ```rust,ignore (partial-example)
 use rustc_codegen_ssa::traits::CodegenBackend;