* VMUserAddressSpace & VMTranslationMap64Bit will need to be inherited from.
* vm_soft_fault & vm_unmap_address_range will need to be invoked directly.
* map_backing_store will need to be invoked directly. The whole concept
of "backing stores" is long merged into VMCache anyway, so at the
same time, just rename the method to "vm_map_cache".
Methods added to the internal vm_priv.h; they should not be needed
except in special circumstances.
Augustin Cavalier
aa731510c1