PATCH: Improve Java build times

[Per Bothner]

Mark Mitchell wrote:
> We should also reopen the question of applying all these patches to the
> branch.  I don't know quite what to think about that.  On the one hand,
> these are definitely not patches to fix regressions.  On the other, if
> we can improve our testing cycle times significantly, that matters.

I think we should at least verify that the patches don't break
when compiling multiple source files at once.  The Kawa Makefiledoes 
compile entire patckages at once, so I guess it's time for me to
re-build Kawa with a re-built trunk.
-- 
	--Per Bothner
per@bothner.com   http://www.bothner.com/per/