Limiting Conan's CPU usage: modern edition

Turns out that my Raspberry Pi doesn't like building on all its cores. The build is so memory heavy after installing the 64 bit version of the OS that it runs out of memory and completely chokes. The obvious way to fix problems like these, particularly when the problem is from concurrent builds, is reducing the amount of cores used. There's still other reasons for limiting Conan's CPU use. I'd list some, but you're here, so I'm sure you've brought your own examples.