re: kern/58425: negation of pid or pgid is UB for INT_MIN

[matthew green <mrg%eterna23.net@localhost>]

>   | This could be a theoretical issue or it could be a practical issue,
>
> I believe that unless we have some architecture which traps when
> executing -INT_MIN rather than just generating INT_MIN as the result

this may not be relevant, but it triggered me. :-)

i recently was dealing with a trap related to exactly this.

i was running atf on m68k virt68k qemu and it crashed the emulator
itself.  turns out -INT_MAX/-1 traps on x86.

i have this uncommited/unsubmitted patch for qemu:

   https://www.netbsd.org/~mrg/patch-target_m68k_op_helper.c


.mrg.