Linus, Alan-

register_sysrq_key() is typed #ifdef CONFIG_MAGIC_SYSRQ,
but untyped if it's not defined, causing problems for callers
when CONFIG_MAGIC_SYSRQ is not defined.
This patch fixes that problem.

arch/i386/kernel/apm.c calls [un]register_sysrq_key() with
a pointer to a sysrq_poweroff_op data structure that is
only declared #ifdef CONFIG_MAGIC_SYSRQ.
This patch also wraps the register/unregister calls with
#ifdef CONFIG_MAGIC_SYSRQ.

~Randy