MSVC

Now that we seem to have MSVC building working tolerably well, I think
we need a bit of cleanup. In particular, I think the config setup needs
to be more like the arguments we pass to the standard configure script.
This shouldn't be hard, but I think it should be done before we go to
beta, if possible. I think the names should match up pretty much one for
one - this should make faking out pg_config easier.

Since this is a perl hash, we'll need to have some sort of mapping
convention. I suggest this:

. where the configure arg doesn't take a value, make the hash value
undef (e.g. '--enable-integer-datetimes' => undef )
. where the configure arg would occur with a single value, just set
that (e.g. '--prefix' => 'c:\\foo' )
. where the configure arg would occur with a multiple value, provide a
listref (e.g. '--with-libs' => [ 'c:\\bar', 'd:\\baz' ] )

Thoughts?

cheers

andrew