`gem install therubyracer` не работает в Mac OS X Lion

Буду признателен за помощь в работе gem install therubyracer. Вот ошибка:

$ gem install therubyracer
Building native extensions.  This could take a while...
ERROR:  Error installing therubyracer:
    ERROR: Failed to build gem native extension.

        /Users/david/.rvm/rubies/ruby-1.9.3-p194/bin/ruby extconf.rb
checking for main() in -lobjc... yes
*** 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=/Users/david/.rvm/rubies/ruby-1.9.3-p194/bin/ruby
    --with-objclib
    --without-objclib
extconf.rb:15:in `<main>': undefined method `include_path' for Libv8:Module (NoMethodError)

Вот некоторые важные шаги, которые я выполнил до ошибки. Они работали нормально:

$ gem install libv8
$ brew install v8

Моя среда:

• Mac OS X Lion 10.7.4
• ruby ​​1.9.3p194 (2012-04-20, редакция 35410) [x86_64-darwin11.4.0] (через rvm)
• V8 версии 3.9.24 (через доморощенный)