Revert to Robert Strandh's version of recompute-extent-for-changed-child, which I appear to have broken.
Revert to Robert Strandh's version of recompute-extent-for-changed-child,
which I appear to have broken.

swflint/McCLIM,onixie/mcclim,antifuchs/mcclim,swflint/McCLIM,onixie/mcclim,swflint/McCLIM,onixie/mcclim,slyrus/mcclim,antifuchs/mcclim,slyrus/mcclim