This moves the register shuffling code into arch/um/os-Linux/sys-$(SUBARCH),
making it purely userspace code.  It also adds an x86_64 implementation of
registers.c.
Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>