Google for a Debian/Arm/qemu-static chroot - -
The is fairly well documented, you have a choice of directions.
The one I found easiest to follow is:
https://wiki.debian.org/ArmHardFloatChroot
Modifying names and things to use the ARMel and the NSLU2 xScale tar-ball in your case.
I have several of those installed and they each worked the first time tried.
Notes:
For the i.MX6 touchscreen devices (they all are) - Debian Jessie is a good match to the system libraries. I haven't found a problem yet.
For the K1 - I think you will be stuck with Debian 3 to get a decent match with the installed system libraries.
Then, since the NSLU2/Debian tar-ball is still posted, run that in your qemu chroot (emulation on a current desktop will be a lot faster than the NSLU2 is
).
https://www.cyrius.com/debian/nslu2/
Note that the Debian 3 tar-bar is still posted there (or linked to from there).
Trivia: The Peter Korsgaard mentioned there is now the lead maintainer of BuildRoot.