Make gpt(8) generate v4 (random) uuids.

Don't needlessly leak your date/time and MAC address when you edit
the disk.

Read from /dev/urandom rather than calling arc4random or anything,
since this is a tool.  (Cygwin seems to have /dev/urandom, but yell
if this breaks the build on your exotic platform because it lacks
/dev/urandom.)

ok apb
Make uuidgen(2) generate v4 (random) uuids.

Rip out all the needless MAC address and date/time leakage.  No more
uuid_init necessary, nor contention over a global uuid state.

While here, simplify uuid_snprintf and fix a strict aliasing
violation.
Paranoia: choke noisily on EOF from /dev/urandom.
Import tzdata2014h from ftp://ftp.iana.org/tz/releases/tzdata2014h.tar.gz

Summary of changes in tzdata2014h (2014-09-25 18:59:03 -0700):
  * America/Jamaica's 1974 spring-forward transition was Jan. 6, not Apr. 28.
  * Shanks says Asia/Novokuznetsk switched from LMT (not "NMT") on 1924-05-01,
    not 1920-01-06.
  * Some more zones have been turned into links, when they differed
    from existing zones only for older time stamps.  As usual,
    these changes affect UTC offsets in pre-1970 time stamps only.
    Their old contents have been moved to the 'backzone' file.
    The affected zones are: Africa/Blantyre, Africa/Bujumbura,
    Africa/Gaborone, Africa/Harare, Africa/Kigali, Africa/Lubumbashi,
    Africa/Lusaka, Africa/Maseru, and Africa/Mbabane.
  * Changes affecting documentation and commentary.
Remove '#line ...' lines to not confuse mkdep(1).
tzdata2014h/tzcode2014h have been released.  we have updated tzdata.
zoneinfo: Import tzdata2014h. [apb 20141004]
Also delete a stray blank line.