No UNSAT

Using MinizincIDE 2.5.2 under _Windows 10_, I do not get **UNSAT** results.

Example:

```
var 1..10: a;

constraint 0 > a * a;

```

Output (similar for various solvers):

```
Running untitled_model.mzn
Finished in 144msec
```

Do I have to set some (hidden?) parameter to get the 

`=====UNSATISFIABLE=====`

of elder releases?