wakeup_flags patch.

[Jeff Roberson]

http://people.freebsd.org/~jeff/wakeupflags.diff

It didn't workout very cleanly since the flags have to go through three 
layers.  I could define wakeup and sleepq flags to be the same and skip a 
bunch of conditionals.  However, we'd then have to know which flags were 
free to use in each case.  Are there any further opinions on the style?

This patch does not include an implementation for WAKEUP_LOCAL.  I'm still 
working on that in SCHED_SMP.  Ironically, it does include an 
implementation for WAKEUP_TAIL, however, I don't have any users of that. 
:-)

Thanks,
Jeff