I noticed that the earlier gdb outputs did not include any backtrace.
So here it is. :-)
bob
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#0 0x00514ead in nr_object_check_instance_type () #1 0x0044630f in nr_arena_item_set_sensitive () #2 0x00ee3f9b in Inkscape::Util::share_string(char const*)::__PRETTY_FUNCTION__ () #3 0x00ee3f6c in Inkscape::Util::share_string(char const*)::__PRETTY_FUNCTION__ () #4 0x00000242 in ?? () #5 0x00515548 in nr_arena_request_render_rect () #6 0x0042863d in sp_item_invoke_show () #7 0x00463a76 in CGroup::_showChildren () #8 0x00465f41 in CGroup::show () #9 0x0042f5bc in sp_root_show () #10 0x00428287 in sp_item_invoke_show () #11 0x00462e22 in SPDesktop::init () #12 0x004df245 in sp_desktop_widget_new () #13 0x004144ec in sp_file_new () #14 0x004149d5 in sp_file_new_default () #15 0x00401d0d in sp_main_gui () #16 0x00408091 in Inkscape::NSApplication::Application::run () #17 0x00402c59 in main () (gdb)