[fpc-pascal] Large file support

[Marco van de Voort]

In our previous episode, Marco van de Voort said:
> 
> FPC_USE_LIBC for linux and *bsd still is still hardly used afaik.
> 
> Maybe we could clean it out. 

These sentences came close together while composing the message, so to be
clear: I didn't mean cleaning out FPC_USE_LIBC, only the fs32bit define(with
only two occurances)