#1 utf-8

[Anonymous]

./configure --help

shows

--with-charset=charset set default charset (euc-jp/sjis/utf-8))

(extra ")" may be a typo.)

but an example on http://mecab.sourceforge.net/#charset
uses

% tar zxfv mecab-ipadic-2.7.0-xxxx
% ./configure --with-charset=utf8
% make

Which is correct utf-8 or utf8 ?

[Nobody/Anonymous]

UTF-8 is correct.