MFC 267929, 267937, 267939, 267940, 267941, 267942, 267987, 268006:

 2915 DTrace in a zone should see "cpu", "curpsinfo", et al
 2916 DTrace in a zone should be able to access fds[]
 2917 DTrace in a zone should have limited provider access
 4477 DTrace should speak JSON
 Add stubs for CTF functions which are not yet implemented.
 4474 DTrace Userland CTF Support
 4475 DTrace userland Keyword
 4476 DTrace tests should be better citizens
 4479 pid provider types
 4480 dof emulation is missing checks
 4471 DTrace count() with histogram
 4472 DTrace full width distribution histograms
 4473 DTrace frequency trails