我想将我的 rails 应用程序部署到 Heoku，所以我制作了新的 rails 应用程序，然后更改了 Gemfile
gem 'sqlite'
至
gem 'pg'
然后我做了
bundle install
在我的终端中（我的开发环境是 Mac OS 10.8.2）并得到以下结果。
Fetching gem metadata from https://rubygems.org/.........
enter code hereUsing rake (0.9.2.2)
Using i18n (0.6.1)
Using multi_json (1.3.6)
Using activesupport (3.2.8)
Using builder (3.0.3)
Using activemodel (3.2.8)
Using erubis (2.7.0)
Using journey (1.0.4)
Using rack (1.4.1)
Using rack-cache (1.2)
Using rack-test (0.6.2)
Using hike (1.2.1)
Using tilt (1.3.3)
Using sprockets (2.1.3)
Using actionpack (3.2.8)
Using mime-types (1.19)
Using polyglot (0.3.3)
Using treetop (1.4.10)
Using mail (2.4.4)
Using actionmailer (3.2.8)
Using arel (3.0.2)
Using tzinfo (0.3.33)
Using activerecord (3.2.8)
Using activeresource (3.2.8)
Using bundler (1.2.0)
Using coffee-script-source (1.3.3)
Using execjs (1.4.0)
Using coffee-script (2.2.0)
Using rack-ssl (1.3.2)
Using json (1.7.5)
Using rdoc (3.12)
Using thor (0.16.0)
Using railties (3.2.8)
Using coffee-rails (3.2.2)
Using jquery-rails (2.1.3)
Installing pg (0.14.1) with native extensions
Gem::Installer::ExtensionBuildError: 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
Using config values from /usr/bin/pg_config
checking for libpq-fe.h... yes
checking for libpq/libpq-fs.h... yes
checking for pg_config_manual.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 ***
Could not create Makefile due to some reason, probably lack of necessary libraries and/or headers. Check the mkmf.log file for more details. You may need configuration options.
Provided configuration options:
--with-opt-dir
--without-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby
--with-pg
--without-pg
--with-pg-dir
--without-pg-dir
--with-pg-include
--without-pg-include=${pg-dir}/include
--with-pg-lib
--without-pg-lib=${pg-dir}/lib
--with-pg-config
--without-pg-config
--with-pg_config
--without-pg_config
--with-pqlib
--without-pqlib
--with-libpqlib
--without-libpqlib
--with-ms/libpqlib
--without-ms/libpqlib
Gem files will remain installed in /Users/haegwankim/.bundler/tmp/44175/gems/pg-0.14.1 for inspection.
Results logged to /Users/haegwankim/.bundler/tmp/44175/gems/pg-0.14.1/ext/gem_make.out
An error occurred while installing pg (0.14.1), and Bundler cannot continue.
Make sure that `gem install pg -v '0.14.1'` succeeds before bundling.</pre>
我做了我能做的一切（谷歌、朋友等）但无法弄清楚。我真的很感激有人可以解决这个问题。干杯!