iconv distinguishes between euc-kr and cp949, while libguess
and libuchardet doesn't (only returns euc-kr). EILSEQ occurs
when the input encoding of iconv is set to euc-kr and if the subs
contain letters not included in euc-kr. Since cp949 is a extension
of euc-kr, choose cp949 instead.
Signed-off-by: wm4 <wm4@nowhere>