Add pointer to errors about not being able to find functions

[EmilHvitfeldt]

In reference to #1072 there are times where functions can't be found when doing things in parallel.

We could detect that this happening after the fact and append the error/add helper to tell the users how to fix this issue "use pkgs argument in control_*() functions

[EmilHvitfeldt]

I don't know where we would do it, as inside tune seems like a bad idea