gnu libiconv（可以下载）

Chinese EUC-CN, HZ, GBK, CP936, GB18030, EUC-TW, BIG5, CP950, BIG5-HKSCS, BIG5-HKSCS:2004, BIG5-HKSCS:2001, BIG5-HKSCS:1999, ISO-2022-CN, ISO-2022-CN-EXT

https://www.gnu.org/software/libiconv/

https://ftp.gnu.org/pub/gnu/libiconv/