from netbsd:

from netbsd:
Extend use of vm_object_prefer() to vm_allocate_with_pager().
Make vm_object_prefer() call MD aligner for "pageless" objects too,
so we can have more control over the virtual address to be used.

Implementation could be simpler if we by-pass the object to mapped, but
we'd loose the ability to adapt alignment to objects that were previously
mmap'ed with MAP_FIXED on.

Only expect vm_fork() to return if __FORK_BRAINDAMAGE is defined.
Eliminate unused third arg to vm_fork().