back port --enable-export-all option in configure script

git-svn-id: http://libtorrent.googlecode.com/svn@10515 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
merged Steven Siloti's peer crypto patch into trunk

git-svn-id: http://libtorrent.googlecode.com/svn@10516 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
added missing include

git-svn-id: http://libtorrent.googlecode.com/svn@10517 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda
merged fixed include

git-svn-id: http://libtorrent.googlecode.com/svn@10518 f43f7eb3-cfe1-5f9d-1b5f-e45aa6702bda