<sys/gpt.h>. This avoids having to include both <sys/uuid.h> and
<uuid.h>, which is considered by your friendly committer to be
aestheticly displeasing (= ballyhoo barf barf :-)
but is useful to have handy. EFI GPT partitions are used instead of the
fdisk+disklabel combination. They are pure 64 bit LBA, are fully
extensible, support up to 16383 partitons per disk, etc.