How to create library with exported functions

[denizzzka]

Hi!

I am make a yet another attempt to create an interface to 
PostgreSQL from the D: https://github.com/denizzzka/dpq2

I can not understand how do I compile it into a library and 
create .di headers file. Currently, "make debug" uses dmd -lib 
and creates libpq.di file, but its file contains only few strings 
from main()

Plz help!