[PATCH][Ada][4.1] Fix cross gnatmake building libraries in project mode

[Arnaud Charlet]

> Tested on 4.1.1 prerelease using a Linux to mingw32 cross compiler.
> 
> I assume mdll-utl.adb needs a similar change, and it seems that the
> problem is also present on mainline (by reading the source).
> 
> I'm not sure there isn't a better fix for all this, any idea about that
> Arnaud?

Your proposed change looks good to me, and an improvement.
I'd say go ahead, assuming successful Ada testing.

> 2006-05-27  Laurent GUERBY  <laurent@guerby.net>
> 
>         PR ada/27769
> 	mlib-utl.adb: Use Program_Name.