diff --git a/src/h/internal.h b/src/h/internal.h
index 19a47486..9237241c 100755
--- a/src/h/internal.h
+++ b/src/h/internal.h
@@ -490,7 +490,7 @@ extern cl_object ecl_waiter_pop(cl_env_ptr the_env, cl_object q);
 
 /* threads/rwlock.d */
 
-#ifdef ECL_RWLOCK
+#ifdef ECL_THREADS
 extern cl_object mp_get_rwlock_read_wait(cl_object lock);
 extern cl_object mp_get_rwlock_write_wait(cl_object lock);
 #endif