I have done "brew install postgresql" got 9.0.2 but running "gem install pg" I get missing library

gem install pg

Building native extensions. This could take a while...

ERROR: Error installing pg:

ERROR: Failed to build gem native extension.

/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby extconf.rb

checking for pg_config... yes

开发者_开发技巧 Using config values from /usr/local/bin/pg_config

checking for libpq-fe.h... yes

checking for libpq/libpq-fs.h... yes

checking for PQconnectdb() in -lpq... no

checking for PQconnectdb() in -llibpq... no

checking for PQconnectdb() in -lms/libpq... no

Can't find the PostgreSQL client library (libpq)

* extconf.rb failed *

It looks like you either need to specify your postgres lib directory:

gem install pg -- --with-pg-dir=/path/to/pg_dir

or perhaps a 32bit vs.64 bit compatibility problem

ARCHFLAGS='-arch x86_64' gem install pg

"env ARCHFLAGS="-arch x86_64" gem install pg" worked for me when using Snow Leopard.