Compile problem ov.cc of octave-3.1.51 on cygwin

[John W. Eaton]

On 28-Jul-2008, Jaroslav Hajek wrote:

| After a little playing around, I've decided it will be best to fix the
| problem in place. See the attached patch. And anyway, this code seems
| even better than the previous one: it will likely avoid a double
| conversion.
| Still, I kind of feel that octave_int<> instances should be implicitly
| convertible to default int
| (or perhaps all integer types), but I see no easy way of doing it.

Should there be at least a warning for values that are out of range?

jwe