struct ibcs_sigframe is not (always?) accurate #27
Description
On x86-64 Linux, the later fields of struct ibcs_sigframe are pretty clearly misaligned, at least for an RT sigframe. Something else is on the stack after the ucontext/mcontext, rather than the siginfo as we currently have. Dig up the references for this, from Linux (but cross-check against IBCS if I can find it documented?).