Progress on AppVeyour

Hi Ramiro,
  I'm following your progress on AppVeyor, quite interesting.

Some things I notes:
- you register odbc driver with odbcconf, you can use regsvr32, the
driver should be able to register itself. Strange to use this program
for registering an odbc driver instead of a COM component but I added
this feature;
- iconv seems not compiled (as tsql output), looks like some checks
are not done in CMakeLists.txt and so some variable are not defined
correctly;
- similar for ODBC, on 64 bit for instance you get lot of problems as
some define are not there (like HAVE_SQLLEN). Not your fault but can
cause problems.

I also added a fix for thread declatation, I'll look forward to see
results from next compile with updated master to to check if they
disappeared. It's a pity a thread returns a DWORD instead of a
DWORD_PTR it's useful to pass a pointerand thread process data passes
and return other data with another pointer.

Frediano