Warning:

!!!!! No such file: /Volumes/HD/workpspace/BS/bin/CMakeExternals/Source/MITK-Data/Sigmoid.nrrd !!!!!
!!!!! No such file: /Volumes/HD/workpspace/BS/bin/CMakeExternals/Source/MITK-Data/Sigmoid-2D-as-3D.nrrd !!!!!

These files don't exist. Just remove the corresponding two lines in Modules/Segmentation/Testing/files.cmake