Milter-greylist

> > After some debugging I figured out where was this coming from.
> > On the mean time I fixed the type of priv->priv_maxpeek,
> > which should be size_t and not int.
> 
> The printf should use %zu now, but that is C99 syntax. How compatible is
> it with various systems that build milter-greylist?
> 

This change wasn't from the printf(),
rather from assignments to that variable
which already has the type size_t:

priv->priv_maxpeek = conf.c_maxpeek;
in milter-greylist.c
where:
 size_t c_maxpeek;
in conf.h

The other option would be to change
c_maxpeek to have type int.