Re: Configurable location for extension .control files

Yes, they do - including a horde of deeply confused and frustrated Rails
users struggling to understand why they're getting "no such file or
directory" or "permission denied" messages about Pg's unix socket,
because of course they're linked to Apple's libpq which has a different
default unix socket path, and unless they explicitly specify `host:
localhost` in their Rails database.yml they get a unix socket connection.

Another option would be to have to explicitly allow use of Apple's
PostgreSQL (based on known install paths) though; think
"--use-system-postgresql".

I get the strong impression from what I've been reading that a fairly

typical Rails user setup is:

* Install homebrew
* Install PostgreSQL using homebrew but don't start it
* Build the Pg gem against homebrew postgresql's libpq
* Download and run postgres.app
* Run your Pg gem using the libpq from homebrew against the postgres.app
server

Ugh.

Good point... though that also raises more concerns regarding consumers

of the Pg library. And extensions, for that matter; if extensions are
out-of-tree you need versioned subdirectories, otherwise you'll have
conflicts between 9.2 and 9.3 (for example) versions of the same extensions.

It's also another issue with libpq. User upgrades Postgres.app and
suddenly their Ruby gems stop working with some linkage error they
probably don't understand.

(All this is, IMO, really a lesson in why Apple should introduce a
non-awful packaging system into OS X).