Merge pull request #21535 from lnicola/proc-macro-srv-cli-link

minor: Fix linking of proc-macro-srv-cli

Author: ChayimFriedman2

crates/proc-macro-srv-cli/src/lib.rs

@@ -2,5 +2,10 @@
 //!
 //! This module exposes the server main loop and protocol format for integration testing.
 
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
+
 #[cfg(feature = "sysroot-abi")]
 pub mod main_loop;

crates/proc-macro-srv-cli/tests/legacy_json.rs

@@ -4,6 +4,10 @@
 //! channels without needing to spawn the actual server and client processes.
 
 #![cfg(feature = "sysroot-abi")]
+#![cfg_attr(feature = "in-rust-tree", feature(rustc_private))]
+
+#[cfg(feature = "in-rust-tree")]
+extern crate rustc_driver as _;
 
 mod common {
     pub(crate) mod utils;