Difference between guix/build and guix/build-system

[Vasilii Smirnov]

I've noticed that build systems in Guix are split in two parts:
- guix/build-system/${name}.scm
- guix/build/${name}-build-system.scm
where ${name} can be "cmake", or "node", etc... So, the question is: 
what's the reason for this split?

If I want to write a new build system, what code should I put in 
"guix/build", and what in "guix/build-system"?