Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy i386 reg.h to x86 and merge with amd64 reg.h. Replace i386/amd64/pc98
reg.h with stubs.

The tREGISTER macros are only made visible on i386. These macros are
deprecated and should not be available on amd64.

The i386 and amd64 versions of struct reg have been renamed to struct
__reg32 and struct __reg64. During compilation either __reg32 or __reg64
is defined as reg depending on the machine architecture. On amd64 the i386
struct is also available as struct reg32 which is used in COMPAT_FREEBSD32
code.

Most of compat/ia32/ia32_reg.h is now IA64 only.

Reviewed by: kib (previous version)

Add reach-over include files to read i386/foo.h. In time, the pc98
specific code will migrate to these files to augment or replace the
version in i386/include and/or i386/linux. This should, in the
fullness of time, allow many of the #ifdef PC98 in the tree.

# These files are in the public domain because there is insufficient
# creative content in them. When you customize them, please add a
# copyright notice and license.

OK'd in principle by: nyan@