Log Message:
* .include "../../devel/readline/buildlink3.mk" with USE_GNU_READLINE=yes
  are replaced with .include "../../devel/readline/buildlink3.mk", and
  USE_GNU_READLINE are removed,

* .include "../../devel/readline/buildlink3.mk" without USE_GNU_READLINE
  are replaced with .include "../../mk/readline.buildlink3.mk".