Auto merge of #126692 - DianQK:nixos-patchelf, r=Nilstrieb

patch `rust-lld` and `ld.lld` on NixOS

When `rustc` uses its self-contained lld, we also need to patch `rust-lld` and `ld.lld`.
The `rpath` for `rust-lld` is `$ORIGIN/../../../:$ORIGIN/../lib`, so I use `--add-rpath` instead of `--set-rpath`, which should be easier to maintain.

I also changed `src/bootstrap/src/core/download.rs`, even this doesn't fix any known issues.

For the `lld-wrapper.sh` of lld, refer to: rust-lang/rustc-dev-guide#1999.