This doesn't add any configurability to ceres_library() yet, but it does correctly determine the include path for use with -I, allowing this to be used as a dependency from other workspaces. Change-Id: I223b6e63c2ea82ab7f552337f78fffd54f20b0e0
Change-Id: I547037460e8ec1fa14438d655c10b261daa39d96