I wrote:
> Heikki Linnakangas <hlinnaka(at)iki(dot)fi> writes:
>> Isn't this bogus?
> No. Note the comment immediately above, as well as the header comment
> for the function.
OTOH, now that I think about it there's no reason whatever for that
bizarre call convention. Let's split the function into two: one to
expand an existing multixact, and one to make a multixact from two
regular xids.
regards, tom lane