[Lazarus] Multiple profile directories

[Mark Morgan Lloyd]

Michael Van Canneyt wrote:

> Just to be complete:
> the sdfdataset unit contains a variable-length component as
> well.

Yes. I was not quite clear, I messed fixed/variable
and limited/unlimited length concepts. TSdfDataSet does have
variable field length but it still requires you to know maximum
field length in advance. This approach improves performance
greatly but is not very convenient in cases where data is less
predictable.