libc - Implement sigblockall() and sigunblockall() (2)
* Cleanup the logic a bit. Store the lwp or proc pointer
in the vm_map_backing structure and make vm_map_fork()
and friends more aware of it.
* Rearrange lwp allocation in [v]fork() to make the pointer(s)
available to vm_fork().
* Put the thread mappings on the lwp's list immediately rather
than waiting for the first fault, which means that per-thread
mappings will be deterministically removed on thread exit
whether any faults happened or not.
* Adjust vmspace_fork*() functions to not propagate 'dead' lwp
mappings for threads that won't exist in the forked process.
Only the lwp mappings for the thread doing the [v]fork() is
retained.
UnifiedSplitRaw
