I took a look App:Stacktrace, It's compiled gdb to perl interpreter. It should work for you unless the internal of perl has been changed much.

But your issue is different, theretcially, when fork create a new process, gdb will only monitor parent process, but your issue happen in child. So I suggest you writing a monitor script to solve this: when your program fork a new process, just sleep a second, find pid of new process, then use App::Stacktrace/gdb attach it.