unix/modos: Allow to configure use of d_ino using _DIRENT_HAVE_D_INO.

Ports will need to #define _DIRENT_HAVE_D_INO (0) to disable d_ino use.

unix/modos.c

@@ -184,7 +184,11 @@ STATIC mp_obj_t listdir_next(mp_obj_t self_in) {
     // DT_UNKNOWN should have 0 value on any reasonable system
     t->items[1] = 0;
     #endif
+    #if !defined(_DIRENT_HAVE_D_INO) || _DIRENT_HAVE_D_INO
     t->items[2] = MP_OBJ_NEW_SMALL_INT(dirent->d_ino);
+    #else
+    t->items[1] = MP_OBJ_NEW_SMALL_INT(0);
+    #endif
     return MP_OBJ_FROM_PTR(t);
 }