Infinite dumping under cygwin

Ben, I have found out what is causing the infinite dumping under cygwin. You added some code in eval.c:flagged_a_squirmer() that adds a lisp backtrace to the error. Unfortunately this gets called and ignored by image_instantation at dump time causing huge transient spikes in memory usage (the string length alone is 250k) this means that the cygwin dump process can never settle on a steady state for the used memory. Making the backtrace Qnil fixes the problem. I'm hoping you have a suggestion for the fix. I'm not convinced that we actually want the stacktrace at all in the case that we are calling with suspended errors. andy