srcdir == objdir build issues [SC take note]

[Bruce Korb]

Phil wrote:
> To remind the audience, what we're talking about had some discussion here:
> 
>     http://gcc.gnu.org/ml/gcc-patches/2002-04/msg00866.html
> 
> and some patching here (note this was before the top-level autoconfiscation):
> 
>     http://gcc.gnu.org/ml/gcc-patches/2002-04/msg01001.html
> 
> 
> I like the idea of making our configury simply require/assume separate
> build dirs, but there's no need to reject an in-srcdir *interface* just
> because maintaining a parallel in-srcdir *implementation* has been a PITA.

That's the right solution.  :)  But it should also include a warning
message, too.  The results won't be where they're expected.  I also
(for my playtime project) found it too much of a pain to maintain both
and chose the opposite solution:  I silently make srcdir != objdir
builds into srcdir == objdir builds.  Either way, but reducing pain is good.