freetds.rb: Enable support for building FreeTDS from HEAD (gitorious)

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
freetds.rb: Add test that calls tsql -C

Signed-off-by: Adam Vandenberg <flangy@gmail.com>
freetds.rb: Enable support for building with --universal

Closes #21309.

Signed-off-by: Adam Vandenberg <flangy@gmail.com>