[gnome-db] compile libgda postgresql provider from git on windows

i usually use/compile libgda from git on windows

sometimes, and i didn't understand why and when, i compile the  
postgresql provider but when i open the gda-browser the provider it  
isn't among those available (same thing for the web provider but i  
don't use it)

if i set GDA_SHOW_PROVIDER_LOADING_ERROR i get an error far too vague  
to understand the problem (access to a non valid memory position (i  
don't know if that's the right english translation))

what could be the reason?

thanks in advance