I see... now there are too many and confusing standards, eh? Poor FOSS developer can't make it because it's way too difficult, eh?
There is one standard for TTY, and it's ANSI. This was, by the way, the only valid TTY standard in 1964, when the writers of Multics decided to completely ignore it.
And what has POSIX to do with the definition of the newline control sequence?