Is there any significant interest in either of these?
Josh Berkus tells me that he would like pg_controldata information, and I was a bit interested in pg_config information, for this reason: I had a report of someone who had configured using --with-libxml but the xml tests actually returned the results that are expected without xml being configured. The regression tests thus passed, but should not have. It occurred to me that if we had a test like
select pg_config('configure') ~ '--with-libxml' as has_xml;
in the xml tests then this failure mode would be detected.