STMT.row_bind_offset is encoded in 32-bit


In `hstmt.h`, `STMT.row_bind_offset` is encoded as a `SQLUINTEGER` which is 32-bit. This can cause some issue for calls to `SQLSetStmtAttr(SQL_ATTR_ROW_BIND_OFFSET_PTR)` on 64-bit platforms as a 64-bit pointer gets cast into a 32-bit value, as seen in `odbc3.c`:

```
stmt->row_bind_offset = (SQLUINTEGER) (SQLULEN) ValuePtr;
```
