[PATCH] ada: Use explicit conversion to VString_Ptr

[Arnaud Charlet]

> >Ok, it got caught by the -gnatw.u warning; if Unchecked_Access is indeed
> >mandatory here, the -gnatw.u patch may be missing a corner case.
> 
> This makes me worry about that patch. I really think we should redo this
> using my approach, which is for sure reliable.

Agreed, sounds like the -gnatw.u warning is dangerous as it is.

Arno