[fpc-devel] Improper OUT usage.

[Marco van de Voort]

In our previous episode, Vincent Snijders said:
> > So be careful if you use OUT with types that have range limitations. Not
> > setting the out parameter can make debug tools like gttt difficult.
> >
> 
> You found a big in fcp-passrc, because if you have an out parameter,
> then the callee has to output a valid variable. If it asumes that is
> initialized when called, then it must use var instead.

I already had changed it to var in r23760. I did want to warn for the
bug's pattern, so I wrote this to the ml.