bundle install / Error in Installing libv8 (3.3.10.4) on rails (running on Lion)

I have added the gem 'sunspot_rails' in my gem file and ran bundle install. I have been getting errors in installing libv8 and the error message is as follows: ``` Installing libv8 (3.3.10.4) with native extensions Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension. /opt/local/bin/ruby extconf.rb *** 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 --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=/opt/local/bin/ruby extconf.rb:13: uninitialized constant Gem (NameError) Checking for Python... Gem files will remain installed in /Users/sonyakim/.rvm/gems/ruby-1.9.2-p290/gems/libv8-3.3.10.4 for inspection. Results logged to /Users/sonyakim/.rvm/gems/ruby-1.9.2-p290/gems/libv8-3.3.10.4/ext/libv8/gem_make.out An error occured while installing libv8 (3.3.10.4), and Bundler cannot continue. Make sure that `gem install libv8 -v '3.3.10.4'` succeeds before bundling. ``` When I run gem install libv8 -v '3.3.10.4', the following error message is printed: ``` Building native extensions. This could take a while... ERROR: Error installing libv8: ERROR: Failed to build gem native extension. /opt/local/bin/ruby extconf.rb *** 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 --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=/opt/local/bin/ruby extconf.rb:13: uninitialized constant Gem (NameError) Checking for Python... Gem files will remain installed in /Users/sonyakim/.rvm/gems/ruby-1.9.2-p290/gems/libv8-3.3.10.4 for inspection. Results logged to /Users/sonyakim/.rvm/gems/ruby-1.9.2-p290/gems/libv8-3.3.10.4/ext/libv8/gem_make.out ``` How can I install libv8 properly?