[fpc-pascal] Namespaces Support

[Marco van de Voort]

In our previous episode, Michael Van Canneyt said:
> > Delphi uses winapi, not windows.
> >
> > And I see no need. There is so much code in use that assumes the standard
> > names, and I don't see a need to force existing codebase users to rename
> > everything just to free up a few unit names for packages that are
> > essentially free to chose their own.
> 
> There is a need. Without it, you will severely cripple the use of default namespaces.
> 
> If someone 
> * defines a namespace 'mycompany', 
> * uses that namespace as the default namespace
> * has a 'classes' unit (or anything else that name-clashes with our units) in that namespace
>    he/she will never be able to use our classes unit again.

Yes. And he deserves it IMHO.

I don't consider (XE2+) scenarios like this a reason to rush the renaming of
units and make dual maintenance between older Delphi versions and FPC
harder, and/or need more configuration.

IOW there are scenarios where freeing up the common identifiers are
important, but as said they are far fetched (since that person would
have to have started with this after XE2, and being blissfully ignorant
of the world before that)