[fpc-pascal]parameter is 0x0 on callback

[Marco van de Voort]

> oncemore for the sake of completeness:
> 
> The 1.9.2 version of fpc is buggy on FreeBSD.
> 
> I get various problems in a method of an object reading its own private
> variables. Some do work, others don't. No scheme of finding out which
> will.

Then it is probably a memory problem. I used 1.9.2 and 1.9.3 a lot, and never
noticed anything.
 
> There may be a coincidence with the order of the vars in the VMT (looks
> as if the first one is the faulty one), but i cannot say so for sure.

> I would really appreciate if this is fixed in 1.9.4.

It will be hard without code to reproduce it.