Pull up following revision(s) (requested by pgoyette in ticket #807):

sys/compat/common/compat_mod.c: revision 1.29

Clean up a stray #ifdef _MODULE - it prevented definition of
COMPAT_SIGCONTEXT which in turn prevented building of the
SYS_compat16_sigaction_14 code.

Should address PR kern/53260

XXX Pull-up to netbsd-8

(martin)