I seems to me that the existing situation is actually correct :
The configuration is a property of the initialized database cluster, so
a logical place for it is in the root of said cluster.
It is *not* a property of the installed binary distribution (e.g
/usr/local/pgsql/etc) - as you may have *several* database clusters
created using *this* binary distribution, each of which requiring a
different configuration.
Having said that, I am ok about the 'include' idea.
regards
Mark