HEADS UP: world needs rebuilding b976e2c

[Rimvydas Jasinskas]

Currently for master users only (w/ likelihood for 4.6-rc soon too):

If you caught b976e2c27a272fede34b02d1900430d3d5ccd624
you need at least updated world to fetch new <machine/cpumask.h>
It does not change ABI so previous kernel should be fine.
In case I m{i,e}ssed something up then - oops Canadian "Sorry".

Also if you happened to get caught into our ipiq fun on 4.7-master and
experiencing some system unresponsiveness "issues", you w.a.n.t
to build and reboot into 743146ae kernel first. Tested consecutive
20x clean buildworlds in <8h on a laptop is stable enough for me.

cpumask.h needs to be done for obvious reasons. Anyone who depended
on previous behavior in their base-external tools and need to keep build
compatibility, the trick is simple:

#include <sys/param.h>
#if __DragonFly_version >= 400600
#include <machine/cpumask.h>
#endif

standard buildworld+buildkernel or quickworld+buildkernel should be
fine, quickkernel works now too. As for realquickkernel well...

### for speedy ones out there, just shoehorn cpumask.h ###
from .../world_x86_64/.../machine to .../sys/$KERNEL/include/machine
### if you don't know what "..." is, then this is not for youTM ###

Cherry-pick for 4.6-rc in 3-5 days.

Thanks,
zrj