COMPAT_FREEBSD would be supported on amd64 if it had its own
freebsd_sigcode.S, freebsd_machdep.c, and freebsd_syscall.c.  Given
that I have virtually no idea what I'm doing insofar as assembly is
concerned--and certainly not x86-64 assembly--I cannot offer to help
with this. :(

--Blair

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