Turning on mpsafe mode by default in master

[Justin C. Sherrill]

On Wed, January 19, 2011 11:27 pm, Matthew Dillon wrote:
>     I'm going to remove the mplock shims in our global tokens in
>     master, essentially running the related code mpsafe from this point
>     on.

If you get the chance, can you benchmark the difference?  I'm curious to
see, say, the difference before and after for a buildworld/buildkernel.