the socket lock was removed in 58c34907 in favour of a global lock -- but the
bootup used an iter_p for create (which is usually called with the lock being
held by the caller)
checks (platform-dependent) all required executables
Vmm_unix.prepare/exec execute solo5-{spt/hvt} depending on the image type
(solo5-elftool figures that out), use jsonm to parse output
Vmm_unix: use ip on linux, no longer ifconfig