About Dub capabilities

[Dukc via Digitalmars-d-learn]

When you want to do things other than just fetching packages, 
invoking D compilers and converting package descriptors, I am 
wondering is Dub up to it?

For example, could dmd source code build (if somebody wanted to) 
be automated with Dub instead of CMake, bearing in mind it 
requires some c++ compilation?

If so, how? I was unable to find anything about custom system 
calls at the website.

Not that I have any need for that right now, I am just interested.