Sorry, I should have been more clear. (was: Re: I would think ...)
You can already run Slackware on various Pi ... See:
https://docs.slackware.com/howtos:hardware:arm:raspberrypi3
For more, see Slackware ARM on Raspberry Pi (SARPi):
http://sarpi.co.uk/
For the record, I'm using a SlackPi as a dedicated development box for my ATmega328 greenhouse project. It's actually quite nice to work with. Recommended.