Really ?... just looking at the source is enough to disqualify an individual from contributing to FPC and Lazarus ?...
Yes. The unit header for e.g XE2 reads as follows:
{*******************************************************}
{ }
{ Delphi Visual Component Library }
{ }
{ Copyright(c) 1995-2011 Embarcadero Technologies, Inc. }
{ }
{*******************************************************}
unit Vcl.Direct2D;
Which means I can not touch it, because I obviously have the sourcecode....
What can be done is clean-room reverse engineering its functionality.
In the past a lot of time and effort has gone into ensuring that FPC or Lazarus weren't in breach of copyright and loads of code have been re-implemented from scratch for that reason.
There are some Delphi's that contain an option to treat it as GPL (not this unit!), but even that is incompatible with LGPL+linker exception as used in both FPC libraries and Lazarus libraries. This requires you also to recompile the particular code with the GPL=true constant set from source.
Note that if you own - like me - a version of Delphi that comes with sourcecode, here XE2, this particular unit can be made to compile with FPC for personal use...
So the issue is not to provide the functionality, but providing the functionality without having seen the Delphi sourcecode. Which means writing it from documentation instead. Which many of us did (not me, I do not have a clean room - actually I have but that are the parts of the house the rest of the family have access to-. But I can spot the use of Delphi code and will report it on Mantis if I see it.)
And before you claim otherwise: this is a clear and stated policy by the developer teams. It is also conforming to international standards and laws. I remember this was a very long and intensive discussion and subsequent repair effort.
I am in no doubt core team can provide you with links and history.
Note that FPC can compile - apart from the system unit - the complete sourcecode of Delphi 5-6-7 rtl and most of VCL, as well as most of 2005-2010 with minor Delphi bug fixes. (read typo's, missing ';''s)
That makes the risks rather high that there is a copyright infringement in submitted code.
And that is what Marco is referring to.