plugin branch initial commit

[Eric Christopher]

Hi All,

On behalf of Sean I've made the initial commit to the gcc plugin  
branch. This work directly applies to the paper that he'll be giving  
at the summit this week. If people want to try out the code and or  
just look and see what direction he's going. If you have any questions  
or comments on the code please let him know - if you're at the summit  
and want to know how to use it just ask him! Otherwise I'm sure he'd  
like mail.

The branch is at:

svn://gcc.gnu.org/svn/gcc/branches/plugin

-eric