many whitespace cleanup.
confirmed "cvs diff -b" are identical.

branches: 1.5.4; 1.5.6;
Whitespace. Portions from Igor Sobrado in PR kern/22595.
Deploy <space><tab> where needed so columns don't teleport when
commenting or uncommenting things.

branches: 1.4.2;
Changes to MEMORY_RBFLAGS option:
- renamed to MEMORY_DISK_RBFLAGS to better fit the rest of the
MEMORY_DISK options(4)
- change default value to RB_AUTOBOOT instead of RB_SINGLE, and adapt
the config(5) files accordingly
- document this option inside options(4)

See also http://mail-index.netbsd.org/tech-kern/2008/12/25/msg003924.html

Reviewed by abs@ in private mail.

branches: 1.3.2; 1.3.6; 1.3.14;
Derive the Xen install kernels from the normal runtime kernels.

branches: 1.2.2; 1.2.4; 1.2.6; 1.2.10;
Merge the bouyer-xeni386 branch. This brings in PAE support to NetBSD xeni386
(domU only). PAE support is enabled by 'options PAE', see the new XEN3PAE_DOMU
and INSTALL_XEN3PAE_DOMU kernel config files.

See the comments in arch/i386/include/{pte.h,pmap.h} to see how it works.
In short, we still handle it as a 2-level MMU, with the second level page
directory being 4 pages in size. pmap switching is done by switching the
L2 pages in the L3 entries, instead of loading %cr3. This is almost required
by Xen, which handle the last L2 page (the one mapping 0xc0000000 - 0xffffffff)
in a very special way. But this approach should also work for native PAE
support if ever supported (in fact, the pmap should almost suport native
PAE, what's missing is bootstrap code in locore.S).

branches: 1.1.2;
file INSTALL_XEN3PAE_DOMU was initially added on branch bouyer-xeni386.