vmem(9) use in Dtrace

[Pedro Giffuni]

Hi;

Just noticed this, in the old DtraceTODO wiki:

https://wiki.freebsd.org/DTraceTODO

There is mention of some use that Dtrace makes of Solaris's vmem
allocator, specifically vmem_create(), vmem_destroy(), vmem_alloc(), and 
vmem_free(). These functions (not exact but similar ones) have
been brought to FreeBSD 10 (r252330).

According to opengrok we may just have to uncomment some Solaris
code in sys/cddl/contrib/opensolaris/uts/common/dtrace/dtrace.c

This would reduce differences with the Solaris code but it has
to be examined carefully as I think John Birrell had already
solved the issue by providing the resource id's natively (kmem).

Just thought I would point it out ... It may be that it is not
worth spending too much time on it since the existing code should
just work.

Pedro.