Oniguruma is a regular expressions library. The characteristics of
this library is that different character encoding for every regular
expression object can be specified.

Supported character encodings: ASCII, UTF-8, UTF-16BE, UTF-16LE,
UTF-32BE, UTF-32LE, EUC-JP, EUC-TW, EUC-KR, EUC-CN, Shift_JIS, Big5, GB
18030, KOI8-R, KOI8, ISO-8859-1, ISO-8859-2, ISO-8859-3, ISO-8859-4,
ISO-8859-5, ISO-8859-6, ISO-8859-7, ISO-8859-8, ISO-8859-9,
ISO-8859-10, ISO-8859-11, ISO-8859-13, ISO-8859-14, ISO-8859-15,
ISO-8859-16.