> gdb `which openscad`
...
(gdb) run
Starting program: /usr/pkg/bin/openscad 

Program received signal SIGSEGV, Segmentation fault.
[Switching to LWP 1]
0x0000000000466795 in builtin_lookup(Context const*, EvalContext const*) ()
(gdb) where
#0  0x0000000000466795 in builtin_lookup(Context const*, EvalContext const*) ()
#1  0x0000000000464866 in BuiltinFunction::evaluate(Context const*, EvalContext const*) const ()
#2  0x0000000000478c43 in ModuleContext::evaluate_function(std::string const&, EvalContext const*) const ()
#3  0x000000000047436f in Context::evaluate_function(std::string const&, EvalContext const*) const ()
#4  0x0000000000478c62 in ModuleContext::evaluate_function(std::string const&, EvalContext const*) const ()
#5  0x0000000000478efd in FileContext::evaluate_function(std::string const&, EvalContext const*) const ()
#6  0x000000000047436f in Context::evaluate_function(std::string const&, EvalContext const*) const ()
#7  0x0000000000478c62 in ModuleContext::evaluate_function(std::string const&, EvalContext const*) const ()
#8  0x000000000046362b in ExpressionFunctionCall::evaluate(Context const*) const ()
#9  0x000000000047593e in ModuleContext::initializeModule(Module const&) ()
#10 0x00000000004712b1 in Module::instantiate(Context const*, ModuleInstantiation const*, EvalContext*) const ()
#11 0x00000000004794ed in FileContext::instantiate_module(ModuleInstantiation const&, EvalContext*) const ()
#12 0x000000000046ed74 in ModuleInstantiation::evaluate(Context const*) const ()
#13 0x000000000046c83b in LocalScope::instantiateChildren(Context const*) const ()
#14 0x000000000046f51e in FileModule::instantiate(Context const*, ModuleInstantiation const*, EvalContext*) ()
#15 0x000000000052152e in MainWindow::instantiateRoot() ()
#16 0x0000000000521c36 in MainWindow::compileDone(bool) ()
#17 0x000000000052b06b in MainWindow::compile(bool, bool) ()
#18 0x0000000000561639 in MainWindow::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) ()
#19 0x00007a9dbc7a17c8 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) ()
   from /usr/pkg/qt4/lib/libQtCore.so.4
#20 0x00007a9dbc7a56a8 in QObject::event(QEvent*) () from /usr/pkg/qt4/lib/libQtCore.so.4
#21 0x00007a9dbef0097c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/pkg/qt4/lib/libQtGui.so.4
#22 0x00007a9dbef068d7 in QApplication::notify(QObject*, QEvent*) () from /usr/pkg/qt4/lib/libQtGui.so.4
#23 0x00007a9dbc791b44 in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/pkg/qt4/lib/libQtCore.so.4
#24 0x00007a9dbc7b8779 in QTimerInfoList::activateTimers() () from /usr/pkg/qt4/lib/libQtCore.so.4
#25 0x00007a9dbc7b8f35 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) ()
   from /usr/pkg/qt4/lib/libQtCore.so.4
#26 0x00007a9dbef8a4cb in QEventDispatcherX11::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) ()
   from /usr/pkg/qt4/lib/libQtGui.so.4
#27 0x00007a9dbc790c0b in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) ()
   from /usr/pkg/qt4/lib/libQtCore.so.4
#28 0x00007a9dbc790e95 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/pkg/qt4/lib/libQtCore.so.4
#29 0x00007a9dbc7956df in QCoreApplication::exec() () from /usr/pkg/qt4/lib/libQtCore.so.4
#30 0x0000000000519fd8 in gui(std::vector<std::string, std::allocator<std::string> >&, boost::filesystem::path const&, int, char**) ()
#31 0x00000000005767db in main ()
(gdb)