fix buffer debugging build

git-svn-id: http://libtorrent.googlecode.com/svn@10562 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
move custom build variants into root Jamfile, to make all regression tests able to use it

git-svn-id: http://libtorrent.googlecode.com/svn@10563 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
move custom build variants into root Jamfile, to make all regression tests able to use it

git-svn-id: http://libtorrent.googlecode.com/svn@10564 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda