Reducing binary size to make compilation fast

[tianyin]

I believe this is something Darko really wants so we should look into it :) So I assign it to @rentingxutx .

@whentojump points me to #5 but #5 is about the kernel.

I completely agree with Darko that we should start from small applications to understand a bit about the mechanism, before dealing with the kernel complexity.

The related talk can be found here: https://www.youtube.com/watch?v=vFWwJrOiVMM&t=8s

And I think @whentojump knows how to attack from the utility perspective.