[fpc-pascal] Array assignment, and not-a-number

[Marco van de Voort]

In our previous episode, Jonas Maebe said:
> > with an appropriate definition of the + operator without risk that an error would try to evaluate it as an ordinary arithmetic expression?
> 
> We don't have constant to identify a qNaN. 

>From math:

       NaN = 0.0/0.0;
       Infinity = 1.0/0.0;
       NegInfinity = -1.0/0.0;


but of course that is just notation/convention (that 0.0/0.0 as literal
evaluates to NaN), it doesn't mean all archs do.