@Turtledog: You're confusing 'using' and 'building'
.
The devteam provides nightlybuilds so, as an user, you don't have to enjoy the wonderful thing that is cross-compilation.
On the other hand, if you do want to help write some code, you will have to use a properly set-up cross-compilation environment. (Can't say what's used on the Kobo, I think the Kobo guys share one, but on the Kindle, a good bet is the next-to-last CodeSourcery TC).
TL;DR: Read the docs
. [As can be guessed from my profile card and the location of this thread, I'm quite unfamiliar with the process on Kobo devices
].