I'd be curious about the GPL and the Gnat version in three cases:
1) I decide to sell a large, complex system, which needs the source
   from one of the Gnat utility packages.  If I include that source
   on the CDROM (say) does the whole thing need to be GPLed?
2) As above, but instead of including the Gnat source module, the
   readme contains instructions for downloading it with Gnat.  Is my
   CDROM now free from GPL requirements?
3) Like (1), but I offer a package of two CDROMS: one contains my
   code, and is copyright, not GPLed, by me, which the second CDROM
   is a copy of all, or just the part my system uses, of Gnat,
   with the usual license on the Gnat CDROM.
4) The above three scenarios, but this time I use a lot of Gnat
   routines in source form, and the actual new code I add is
   rather small.
My impression is that the answers are 1)yes, it's all GPLed, 2) my CDROM
is free from GPL requirements, 3) I don't know, and the answers to 4)
are the same, ie, the size of my added contribution doesn't matter.
  What are the correct answers?