coding-system-change-text-conversion is a compiled Lisp function in `mule-cmds.el'.

(coding-system-change-text-conversion CODING-SYSTEM CODING)

Return a coding system which differs from CODING-SYSTEM in text conversion.
The returned coding system converts text by CODING
but end-of-line as the same way as CODING-SYSTEM.
If CODING is nil, the returned coding system detects
how text is formatted automatically while decoding.