diff --git a/src/obj_stubs.c b/src/obj_stubs.c
index ce0d60d..90cec94 100644
--- a/src/obj_stubs.c
+++ b/src/obj_stubs.c
@@ -2,7 +2,8 @@
 #include <caml/mlvalues.h>
 // only used for public release;
 // internally this is implemented by caml_dummy_obj_is_stack in compiler runtime
-CAMLprim value caml_dummy_obj_is_stack(__attribute__((unused)) value blk) {
+CAMLprim value caml_dummy_obj_is_stack(value blk) {
+  (void)blk;
   // Public compilers don't support stack allocation, so we always return 0
   return Val_int(0);
 }