Well, actually I think they mean support for ARM CPUs running Linux, so this may not just work on the raspberry, but even on your iPhone if you install a linux there!
Anyway, I spend a lot of time today working on building plugins for linux with ARM.
In the next days I will try to get everything compiled and linked. We'll see how well that works.
Same as with 64-bit: Even if it compiles, we need a lot of time to try things.
Things that compile for ARM already include DynaPDF, LargePicture and LCMS2.