See this thread (with solution) on the freecad forum: http://forum.freecadweb.org/viewtopic.php?f=4&t=13728&p=109598 "Compilation of 0.16pre fails on Debian in GCS.cpp"
0.16pre probably builds fine, because the change in GCS.cpp is already done. Any chance to get 0.16(_pre) into unstable soon? That would increase chances to solve any build problems in time to have 0.16 (final) in Stretch.
