I recently ran into an issue like the one listed in issue
#89, however, I have libpq-dev installed. I posted to StackOverflow (http://stackoverflow.com/questions/8814924/gem-install-pg-can-not-bind-to-libpq) and was advised to submit a bug report; uninstalling and re-installing dependencies did not seem to do much.
The results of gem_make.out,
ldd /usr/lib/libpq.so, and mkmf.log can be found in this gist: https://gist.github.com/d05a81701d968895c730
I am running: ruby 1.9.3p0 (2011-10-30 revision 33570) [i686-linux] rvm 1.10.1 (system) gem 1.8.15 psql (PostgreSQL) 8.4.9 (from Ubuntu's repo)
Manually specifying the path to
pg_config does not appear to change anything. It seems as if it's not using pg_config for all values (pg_config --libs, in particular).
The problem began occurring after upgrading to Ruby 1.9.3 from 1.9.2 using
rvm install 1.9.3 && rvm use --default 1.9.3 && rvmsudo gem install pg, however, after reverting to 1.9.2 and attempting to re-install the gem the problem persists (even though it was working fine before).