[fpc-pascal] RunError(215) occurs only in win 64 bit, not win 32 bit

[Marco van de Voort]

In our previous episode, Dennis said:
> When I compiled the following simply programs using Lazarus 1.8  fpc 
> 3.0.4 Win 64, run it, it will throws RunError(215) Arithmetic overflow 
> error.

Which seems correct. The expression to compare with is entirely longword and
it gets negative (5+5) - (10+10).