[LEAPSECS] Running on TAI

[Steve Summit]

Martin Burnicki wrote:
> It's even the same if you look at different struct timespecs taken on
> the same system, but with different clock IDs. From the data type alone
> you don't know how to interpret this correctly.

We've got waaay too many time structures already, but if anyone's
in a position to standardize new ones and have them taken seriously:
a tagged struct timespec, that carries its clock ID along with it,
would be huge.