Remove CRT (C's runtime) from betterC binaries?

[Rel]

> There are other ways to do minimalist programming in D without 
> -betterC. See 
> https://dlang.org/changelog/2.079.0.html#minimal_runtime

Well, what would be the difference between betterC and writing my 
own minimal runtime? For the time being doing betterC looks 
preferable, so I don't need to reimplement some runtime stuff. 
Just recompiling the same program with empty object module gives 
me few errors like size_t, string and etc not implemented in 
object module.