Only set the working path if the variable is set
Only set the working path if the variable is set

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