rustc: Make the generic C stack function signature include a usable return value

src/comp/back/upcall.rs

@@ -83,7 +83,7 @@ fn decl_with_taskptr(taskptr_type: TypeRef, llmod: ModuleRef, name: str,
           dynastack_free: d("dynastack_free", [T_ptr(T_i8())], T_void()),
           alloc_c_stack: dr("alloc_c_stack", [T_size_t()], T_ptr(T_i8())),
           call_c_stack: dr("call_c_stack",
-                           [T_ptr(T_fn([], T_void())), T_ptr(T_i8())],
+                           [T_ptr(T_fn([], T_int())), T_ptr(T_i8())],
                            T_int()),
           rust_personality: dr("rust_personality", [], T_i32())
          };

src/comp/middle/trans.rs

@@ -5792,7 +5792,7 @@ fn register_native_fn(ccx: @crate_ctxt, sp: span, path: [str], name: str,
         cast_to_i32 = true;
       }
       ast::native_abi_c_stack_cdecl. {
-        let llfn = decl_cdecl_fn(ccx.llmod, name, T_fn([], T_void()));
+        let llfn = decl_cdecl_fn(ccx.llmod, name, T_fn([], T_int()));
         ccx.item_ids.insert(id, llfn);
         ccx.item_symbols.insert(id, name);
         ret;