[fpc-pascal] NAN for double

[Marco van de Voort]

> > > How to set a double to NAN (not a number)?
> > > I only found a IsNAN in the math unit.
> > 
> > const nan=0/0;
> 
> unit1.pas(28,10) Error: Division by zero

Afaik that is delphi mode only. Also check the "typ" unit of numlib (in
packages)