Thanks for your comments Andres, I will ignore it for the processes which do not have access to ProcSignal. I will make the changes and post a patch for this soon.
I think that's sensible.
I've had variable results with glibc's backtrace(), especially on older platforms and/or with external debuginfo, but it's much better than nothing. It's often not feasible to get someone to install gdb and run commands on their production systems - they can be isolated and firewalled or hobbled by painful change policies. Something basic built-in to postgres, even if basic, is likely to come in very handy.
