Since upgrading - where there was a message to close xscreensaver due to the change in the C libraries - some of these have stopped working here.
Working: binary horizon, glblur, glmatrix, glslideshow, substrate etc
Not: glschool, photopile
The ones that aren't working show a red "crashed with a SIGABRT" (glschool) or ".. SIGSEGV" (photopile) error message.
glschool will show ok in the small preview, but not full screen or activate.
xscreensaver version 6.02+dfsg1-2ubuntu1