Fix bug in universe where if upgrade_checks wants a new make,
it gets built 16 times in parallel in the same location.
While we are at it, until we finish getting rid of fmake,
be explicit about the make we want to use, thus avoid the problem
of the temp make being the wrong version.

Reviewed by:	obrien
Further restrict the MAC addresses that we use for UUID generation
to those that are universally administered. While it is possible to
add locally administered MAC addresses, it's unclear whether those
are (expected) to be more unique than random multicast MAC addresses
or not.

With many U-Boot configurations assigning fixed and non-official MAC
addresses to ethernet ports and without setting the 'X' flag, this
change may have very little value in the embedded (development)
space. Uniqueness of the universally administered addresses is non-
existent on the (H/W) bench and questionable under the (S/W) desk.
In short: this change is aimed at production environments...