Hardware is rad1o. It based for hackrf. More info at https://rad1o.badge.events.ccc.de/hardware
About toolchain. Makefile.inc give some kind answer for that. I dont have better answer for that because I am really noob with cross compile. Direct link for that https://github.com/rad1o/f1rmware/blob/master/Makefile.inc and looks that it is unusual distinct. So it can (or not) give good answer for more experienced person.