I've seen these warnings when building the latest sources
display/canvas-arena.cpp: In function `void sp_canvas_arena_class_init(SPCanvasArenaClass*)': display/canvas-arena.cpp:91: warning: invalid access to non-static data member `SPCanvasArenaClass::arena_event' of NULL object display/canvas-arena.cpp:91: warning: (perhaps the `offsetof' macro was used incorrectly)
display/sp-canvas.cpp: In function `void sp_canvas_item_class_init(SPCanvasItemClass*)': display/sp-canvas.cpp:110: warning: invalid access to non-static data member `SPCanvasItemClass::event' of NULL object display/sp-canvas.cpp:110: warning: (perhaps the `offsetof' macro was used incorrectly)
Someone familiar with the area these are in should take a look. I do think these should be corrected, just not sure of the "proper" fix.