Well, apparently no one has attempted to compile that IEEE I/O code in 8.1 for a while. C99 says that floats are implemented according to IEEE when the hardware uses it, so the question is if there is ever a case where the C-code is needed.
On the other hand, the reason why I started to look at this is to be able to read and write 128-bit IEEE numbers, so I might need the code for that.