Patch: Increase boehm-gc MAX_ROOT_SETS

[Bryce McKinlay]

Boehm, Hans wrote:

>Wouldn't it be better to just make LARGE_CONFIG the default, as Andrew
>suggested?
>
>I think that most gcj apps are big enough that the extra constant space
>overhead should be in the noise.  And it potentially avoids some other
>issues with very large heaps.
>  
>

For the branch, I wanted to solve the problem while making the least 
intrusive change possible. On HEAD, it sounds like LARGE_CONFIG is the 
way to go. I will test a patch shortly and reverse the MAX_ROOT_SETS 
change there.

Bryce