Get the diff against the checkout's HEAD commit
Get the diff against the checkout's HEAD commit

Without this, changes in the index are not saved.

mathstuf/sprokit,Kitware/sprokit,mathstuf/sprokit,linus-sherrill/sprokit,linus-sherrill/sprokit,linus-sherrill/sprokit,Kitware/sprokit,linus-sherrill/sprokit,Kitware/sprokit,mathstuf/sprokit,Kitware/sprokit,mathstuf/sprokit