Remove unused intercrate dependencies

compiler/rustc/src/main.rs

@@ -1,5 +1,7 @@
 // We need this feature as it changes `dylib` linking behavior and allows us to link to `rustc_driver`.
 #![feature(rustc_private)]
+// Several crates are depended upon but unused so that they are present in the sysroot
+#![expect(unused_crate_dependencies)]
 
 // A note about jemalloc: rustc uses jemalloc when built for CI and
 // distribution. The obvious way to do this is with the `#[global_allocator]`