How to signify a rebuild in the version string for psycopg2?

Since I am looking at doing a rebuild of psycopg2 2.0.12 for windows, I am 
curious what the community think on how I should modify the version 
string, so one can tell what build (or I guess rebuild) it is.

I do not want to add another '.'+number, as I believe that should be 
reserved for code changes.

I was thinking adding an '_'+number, ie 2.0.12_1, but I do not know if 
that would cause problems with code for anyone parsing the version string 
(ie, splitting on the '.', and then doing an int() on the splitted 
values).


Any suggestions, ideas, input, etc, regarding this?

-jason