GNAT ACT source tree

[Robert Dewar]

> 
> This was actually a transient error in our sources, which will be fixed
> with the next mirror.


Perhaps that is a good opportunity to emphasize that in general there is
no guarantee that the set of files available here will bootstrap or be
error free. This is an unmolested view of the current top-of-the-tree at
ACT, and such errors may occur from time to time. They will usually get
fixed right away, as we see them in our nightly builds.