Some platforms, e.g. FreeBSD, support user space setjmp
semantics in kernel.
Reviewed-by: Igor Kozhukhov <igor@dilos.org>
Reviewed-by: Ryan Moeller <ryan@ixsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Matt Macy <mmacy@FreeBSD.org>
Closes#9450