[boehm-gc] Fix libjava "PACKAGE_* redefined" errors

[Hans Boehm]

On Fri, 26 Nov 2004, Bryce McKinlay wrote:

> Probably, we should also get rid of libjava's use of THREAD_LOCAL_ALLOC,
> and simply assume that its always on?
>
That's a little tricky.  The GC currently knows how to do thread-local
allocation only on some platforms (Linux, HP/UX, and a few others).
See boehm-gc/configure.ac for details.

I'm hoping to make thread-local allocation completely transparent to the
client, i.e. libgcj, in gc7, and to support it on additional platforms.
At that point, the problem should disappear.  For now, I'm not sure
how to get rid of the reference to THREAD_LOCAL_ALLOC without reproducing
the logic in boehm-gc's configure.ac, which would be even uglier.

Hans