[PATCH] PR ada/42254, avoid providing multiple copies of object files to link of GNAT tools

[Arnaud Charlet]

> The problem I see with that is that TOOLS_LIBS is used elsewhere - 
> specifically in the targets ../../gnatmake$(exeext), ../../gnatlink$(exeext). 
> These two use the gnatbind -C option and ignore the object file/option 
> list, instead using GNATMAKE_OBJS for the local files, TOOLS_LIBS, 
> and LIBGNAT for the RTS files. So we'd be back where we started from. 
> Also, not clear where to put the dependency that causes libgnatc$(arext) 
> to be built.

OK, let's skip this idea for now then.

> > Changing NOSTDLIB to TOOLS_NOSTDLIB also seems like a good idea.
> 
> OK (and I'll set it to empty at the top).

Assuming your build/testing goes fine with these changes, this is OK, although
I don't think it's a good idea to make these changes now (so late in the
build process), since it's not a regression, and the change has some non
negligible chances of breaking existing builds/ports.

So I'd suggest committing this change on trunk after 4.5 is branched, and
possibly consider backporting the change if it does not cause troubles
on trunk.

Arno