bug#960: 23.0.60; excess consing

[Richard M. Stallman]

    `message' calls `format', which calls `copy-sequence'... Isn't that a
    source of consing?

That seems to account for most of it.  I made another command
that accumulates data in a list, and it showed very little
consing.

This shows that calling `message' does a lot more consing than it
ought to need to do.  But this may not be significant for the great
consing-related slowness I see.