Provide pg_amcheck with an --install-missing option
This will install amcheck in the database if not present. The default
schema is for the extension is pg_catalog, but this can be overridden by
providing a value for the option.
Mark Dilger, slightly editorialized by me.
(rather divergent)
Discussion: https://postgr.es/m/
bdc0f7c2-09e3-ee57-8471-
569dfb509234@dunslane.net