declare-equiv-charset
declare-equiv-charset is a built-in function in `C source code
'.
(declare-equiv-charset DIMENSION CHARS FINAL-CHAR CHARSET)
Declare an equivalent charset for ISO-2022 decoding.
On decoding by an ISO-2022 base coding system, when a charset
specified by DIMENSION, CHARS, and FINAL-CHAR is designated, behave as
if CHARSET is designated instead.