Revert change to apply_patches to fix panic

Author: bjorn3

compiler/rustc_codegen_cranelift/build_system/prepare.rs

@@ -203,7 +203,12 @@ pub(crate) fn apply_patches(dirs: &Dirs, crate_name: &str, source_dir: &Path, ta
     eprintln!("[COPY] {crate_name} source");
 
     ensure_empty_dir(target_dir);
-    copy_dir_recursively(source_dir, target_dir);
+    if crate_name == "stdlib" {
+        fs::create_dir(target_dir.join("library")).unwrap();
+        copy_dir_recursively(&source_dir.join("library"), &target_dir.join("library"));
+    } else {
+        copy_dir_recursively(source_dir, target_dir);
+    }
 
     init_git_repo(target_dir);