[gtkada] patch for mac

[Arnaud Charlet]

> My patch works with configure, but you wanted it moved backwards a bit. 

Right, configure is automatically generated, so you can't modify it.

>   i don't know how to do that, however one of the folks on gnat mac 
> mailing list is working on it.
> 
> perhaps the patch file could be put in the distribution so that mac 
> folks could apply it themselves if they wanted to for now?

Assuming that it still applies to current sources, we could put it in the
contrib directory, yes.

Arno