--with-libedit-preferred is bad design

Hackers,

So I've been trying to compile PostgreSQL with libedit instead of
readline on a linux system, because of a bug in readline (will blog
about it later). This took 5 attempts, because of the peculiar nature
of our readline options in configure:

--without-readline

"compile without readline *or* libedit"

--with-libedit-preferred

"compile with libedit, but if there's an issue with libedit, then
silently substitute readline without telling me"

There's no option where I can say "please compile with libedit, and if
you can't, throw an error". In fact, if libedit isn't found, that's not
even reported in config.log -- your only way to find out you still have
readline is to ldd your psql after it's built.

For that matter, I find it hard to imagine where I would possibly want
the current functionality of --with-libedit-preferred. If I've asked
for libedit, then it's pretty darned sure it's because I don't want
readline.

I think the current --with-libedit-preferred should go away, and be
replaced by a --with-libedit option which throws an error if libedit
isn't found.

Feedback?

--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com