It must be a new thing — I’ve never had anything in /usr/local/etc before, and never had to specify my config file in /etc …
Perhaps the installation process now creates a config file in /usr/local/etc.
Ah, yeah. that’s a FEATURE!
make without a prefix (–prefix=/usr) sets up the config file to work from /usr/local (as that’s where you’ve chosen to install it, by not specifying a prefix). And in fact, the app honors that. The idea being that make; make install works out of the box, even if you –prefix it.
kind of non-intuitive, but least surprising, I think, and I’d argue the “Right Thing”.