svn:externs should not be considered modifications

As part of my job, I work on a large svn project with a lot of externs (152, to be exact).  powerline-shell wants to track each extern as a modification, so I always have "152 + the actual number of local modifications."  I feel like powerline-shell should ignore those externs as changes.  Svn doesn't consider those to be changes, nor does a top-level "svn commit" spider down into the externs (you have to go into each extern and commit there if you have modifications in them).