#else
# define lock_define(name)
# define lock_init(lock) 0
-# define lock_fini(lock) 0
-# define lock_lock(lock) ((void) 0)
+# define lock_fini(lock) ((void) 0)
+ /* The 'dfa' avoids an "unused variable 'dfa'" warning from GCC. */
+# define lock_lock(lock) ((void) dfa)
# define lock_unlock(lock) ((void) 0)
#endif