An (un)privileged user can easily make the kernel dereference a NULL
pointer.

The kernel allows 'data' to be NULL; it's the fs's responsibility to
ensure that it isn't NULL (if the fs actually needs data).

ok christos@
Some fs's - like kernfs - set their vfs_min_mount_data to zero. Add a check
to prevent an (un)privileged user from requesting a zero-sized allocation
(and thus a panic).
Undef possible macro versions of memcpy and friends for kernel builds
too. libkern sometimes defines them to the builtins.
Teach sscom attachment, also the console, to use the busspace handle of the
main register space.

While here, map in the correct amount of memory or bus_space_map() won't
return an error but will wedge the system.
Pendantic structure member initialization.  (setting a field to 0 which is 0).
Reparent children of a dying lwproc.  Fixes wpa_supplicant -B (and
most likely a bunch of other things).
Allow l2cc base to gotten from device properties.
Add ctcom
Do softints after restoring interrupts