Some information about MinGW and SQLServer support.
Thanks to Jeff Henrikson

SQLDriverConnect is exposed to Caml as

# connect_driver;;
- : ?prompt:bool -> string -> Ocamlodbc.connection = <fun>

This allows SQLServer "trusted authentication" mode based on NT domain
identities.  An example connection string is:

let db = connect_driver "Driver={SQL
Server};SERVER=FOOSERVER;Trusted_Connection=yes;Database=MYDB";;

The SQLDriverConnect is only supported with runtime ODBC v2 or greater.
Accordingly, a #define symbol ODBC2 activates odbc2.  Note that pointer
conventions are different in ODBC2, so there is another #define
OLD_POINTERS, which is default on unless ODBC2 is on.  There are also
some debugging printfs which you may delete, clearly marked by DEBUG3.

A build shell script for the mingw toolchain is called INSTALL_mingw.sh,
by analogy with INSTALL_win32.bat.  Note the command line option
-DODBC2.  autoconf integration is not attempted at this time.