We just got our first PR on this, so I've committed it to 2.1-dev, suggested it for merge in APACHE_2_0_BRANCH/STATUS, and mentioned the patch in
http://www.apache.org/dist/httpd/patches/apply_to_2.0.45/
(My apologies to Justin in case he disagrees with the way I put his code to work.)
FWIW, I would have put the logic into APR_SUBDIR_CONFIG by adding a third parameter that lists what options to drop before calling the subdir's configure. This way the logic can be abstracted by the calling functions. This would make it a little bit easier and cleaner to use.
However, I'm currently swamped, so don't expect me to be able to come up with a patch that does this. =-) -- justin