コミットメールを送れるようにしたら、commitする時に
次のような警告が出ます。どうやったらなおるでしょうか？

perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
LANGUAGE = (unset),
LC_ALL = "en_US",
LC_MESSAGES = "en_US",
LC_TIME = "en_US",
LC_NUMERIC = "en_US",
LC_MONETARY = "en_US",
LC_COLLATE = "en_US",
LANG = "en_US"
are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").