TCP_KEEPIDLE on kfreebsd

[peter green <peter.green@postgrad.manchester.ac.uk>]

While looking at why stud FTBFS on all architectures except i386 and 
amd64 (as part of looking at armhf build failures to try to increase 
armhf's build percentage) I decided to take a look at why it wasn't 
building on kfreebsd. I discovered that it was trying to use the socket 
option TCP_KEEPIDLE.

Does freebsd/kfreebsd have an equivilent to this socket option?