Assign internal linkage to autogenerated FnOnce::call_once() instances.

Author: michaelwoerister

src/librustc_trans/closure.rs

@@ -257,7 +257,7 @@ fn trans_fn_once_adapter_shim<'a, 'tcx>(
 
     // Create the by-value helper.
     let function_name = method_instance.symbol_name(ccx.shared());
-    let lloncefn = declare::declare_fn(ccx, &function_name, llonce_fn_ty);
+    let lloncefn = declare::define_internal_fn(ccx, &function_name, llonce_fn_ty);
     attributes::set_frame_pointer_elimination(ccx, lloncefn);
 
     let (block_arena, fcx): (TypedArena<_>, FunctionContext);