Refer to standard library macros by an absolute path

Author: dtolnay

macro/src/expand.rs

@@ -1094,7 +1094,7 @@ fn expand_rust_function_shim_impl(
         #[doc(hidden)]
         #[export_name = #link_name]
         unsafe extern "C" fn #local_name #generics(#(#all_args,)* #outparam #pointer) #ret {
-            let __fn = concat!(module_path!(), #prevent_unwind_label);
+            let __fn = ::cxx::private::concat!(::cxx::private::module_path!(), #prevent_unwind_label);
             #wrap_super
             #expr
         }

src/lib.rs

@@ -508,6 +508,7 @@ pub mod private {
     pub use crate::unique_ptr::UniquePtrTarget;
     pub use crate::unwind::prevent_unwind;
     pub use crate::weak_ptr::WeakPtrTarget;
+    pub use core::{concat, module_path};
     pub use cxxbridge_macro::type_id;
 }