Patched odbc_dfw for PG >= 9.2

Heillo,

after stumbling across compile errors for odbc_fdw I realised it was
still on the 9.1. level.

I've patched it, based on the tds_fdw code (so it's still read-only).

It does compile, and I think it is generally sane, however I'm _anything
but a C hacker_, so whoever feels confident enough please review this,
or even add the write capability :)

As I've been playing around with tds_fdw before and just wanted to see
if I can get around my encoding issues with odbc_fdw, I will not be able
to test it for a few days though.

It is available at
https://github.com/bluthg/odbc_fdw

According notes have been added to the Foreign_data_wrappers WIKI page
as well (no need for more people to try compiling it ;-).

Cheers,

--
Gunnar "Nick" Bluth
RHCE/SCLA

Mobil   +49 172 8853339
Email: gunnar.bluth@pro-open.de
__________________________________________________________________________
In 1984 mainstream users were choosing VMS over UNIX.  Ten years later
they are choosing Windows over UNIX.  What part of that message aren't you
getting? - Tom Payne