Support rpath with -Clinker-flavor=ld

Using `cc_args` panics when using `-Clinker-flavor=ld`, because the
arguments are in a form tailored for `-Clinker-flavor=gcc`.

So instead, we use `link_args` and let that wrap the arguments with the
appropriate `-Wl` or `-Xlinker` when needed.

compiler/rustc_codegen_ssa/src/back/link.rs

@@ -1384,7 +1384,7 @@ fn link_sanitizer_runtime(
         let filename = format!("rustc{channel}_rt.{name}");
         let path = find_sanitizer_runtime(sess, &filename);
         let rpath = path.to_str().expect("non-utf8 component in path");
-        linker.cc_args(&["-Wl,-rpath", "-Xlinker", rpath]);
+        linker.link_args(&["-rpath", rpath]);
         linker.link_dylib_by_name(&filename, false, true);
     } else if sess.target.is_like_msvc && flavor == LinkerFlavor::Msvc(Lld::No) && name == "asan" {
         // MSVC provides the `/INFERASANLIBS` argument to automatically find the
@@ -2208,7 +2208,7 @@ fn add_rpath_args(
             is_like_osx: sess.target.is_like_osx,
             linker_is_gnu: sess.target.linker_flavor.is_gnu(),
         };
-        cmd.cc_args(&rpath::get_rpath_flags(&rpath_config));
+        cmd.link_args(&rpath::get_rpath_linker_args(&rpath_config));
     }
 }