Add comment after endif

* i386/i386/io_perm.h (_I386_IO_PERM_H_): Add comment after endif.
i386/include/mach/i386/mach_i386_types.h: add comments after else and endif

* i386/include/mach/i386/mach_i386_types.h (MACH_KERNEL): Add comments after else and endif.
Make sure cursor is initialized

* i386/i386at/kd.c (kd_xga_init): Add start, stop variables, read them
from CRT registers, make sure the cursor is enabled and is not reduced
to 0, and write them back to CRT registers.
* i386/i386at/kd.h (C_START, C_STOP): New macros.
vm: remove NS32000-specific padding from struct vm_page

Apparently, the NS32000 was a 32-bit CPU from the 1990ies.  The string
"ns32000" appears nowhere else in the source.

* vm/vm_page.h (struct vm_page): Remove NS32000-specific padding.
vm: merge the two bit fields in struct vm_page

* vm/vm_page.h (struct vm_page): Merge the two bit fields.
vm: reduce the size of struct vm_page

Previously, the bit field left 31 bits unused.  By reducing the size
of wire_count by one bit, the size of the whole struct is reduced by
four bytes.

* vm/vm_page.h (struct vm_page): Reduce the size of wire_count to 15
bits.
kern: reduce the size of struct task

* kern/task.h (struct task): Reduce the size of struct task by
2 * sizeof boolean_t by using a bit field for the boolean flags.
kern: make struct kmem_cache fit into two cache lines

Previously, the size of struct kmem_cache was 136 bytes, just eight
bytes larger than 128 bytes, which is typically two cache lines on
today's CPUs.

By reducing the size of the name field which holds a human-readable
description by eight bytes to 24 bytes, the struct kmem_cache can be
made fit into two cache lines.  This change should not affect the
usefulness of this field.  For reference, the length of the largest
hard-coded name is 17.

* kern/slab.h (KMEM_CACHE_NAME_SIZE): Define to 24.