Oh my golly, looks like I picked a "charging only" USB cable. Switched cable, purged .deb package, installed runtime, applied udev rules, installed .deb package.
Works now without the above mentioned error about the rand() function.
Next time no more "jaja, ich weiss how to install a debian package" half-assed-non-reading of the fine instructions.
Apologies for wasting your time!
Ah ha. Was the intent always to have users install both the deb and the runtime?
Maybe you had an arm toolchain installed before you installed the deb. Are we sure that the deb pulls in the toolchain? Need to check that.
Yes, I likely have installed an Arm toolchain installed since I was dabbling with Armbian (sans Docker) some time ago.
Sorry again, and thank you for your patience!
(Ordered an Axocontrol board today. Looking forward to the delivery)
At least the half functional cable is not going to trip me up again.
BTW doing the same with CAT 5 Ethernet cables after I discovered bosses mother is rescuing them from the trash.
@jsilence your not the first ( and won’t be the last) to be fooled by a usb power only cable 
Glad it’s working.
( Sorry, it’s partly my fault I’ve not been doing a lot on the forum recently so haS forgotten some of the common pitfalls.)
