Log Message:
Update to 7900, based on patches provided by Yamashiro, Jun in PR 34651.
Additionally, split option handling into options.mk and properly handle
the configuration file.

Changelog in anthy(7100 to 7900):
* Fix Japanese convert algorithm
* Update main Japanese Kana-Kanji dictionary

Changelog in pkgsrc:
* Fix option for additional Kana-Kanji dictionary.
* Update Okinawa dicrectory(optional).