buildfarm breakage

It looks like some recent patches have broken a couple of things on the 
buildfarm.

Mingw builds are missing in6addr_any in backend/libpq/auth.c, added by a 
recent RADIUS support fix. Looks like we might need to include win32.h 
in there.

MSVC builds are broken from a missing _isnan function on the ECPG tests. 
Do we need to link in a math lib or something there?

Our Solaris *moth members seem to have stopped building. Have we lost them?

cheers

andrew