QQuickDefaultClipNode memory faults

In case of having a radius QQuickDefaultClipNode allocates not enough memory, followed by writing to unallocated memory.

In qquickclipnode.cpp line 90 you find: "g->allocate((segments + 1) * 2)", but it has to be: "g->allocate((segments + 1) * 4);"

We have segments top + border and for each segment 2 points -> 4.

This bug is so fundamental and can probably be found in all versions of Qt 5 ( didn't check it ), that it gives me the impression, that nobody ever used clips with rounded borders - at least not by using this class.