ruby-on-rails-3 – Rails：安装rubyracer时出错

Installing therubyracer (0.11.0) 
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

    /usr/local/bin/ruby extconf.rb 
checking for main() in -lpthread... 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
--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=/usr/local/bin/ruby
--with-pthreadlib
--without-pthreadlib
--enable-debug
--disable-debug
/usr/local/lib/ruby/gems/1.9.1/gems/therubyracer-0.11.0/ext/v8/build.rb:50:in `build_with_rubygem_libv8': undefined local variable or method `libv8_include_flags' for main:Object (NameError)
from extconf.rb:20:in `<main>'


Gem files will remain installed in /usr/local/lib/ruby/gems/1.9.1/gems/therubyracer-0.11.0 for inspection.
Results logged to /usr/local/lib/ruby/gems/1.9.1/gems/therubyracer-0.11.0/ext/v8/gem_make.out

An error occurred while installing therubyracer (0.11.0),and Bundler cannot continue.
Make sure that `gem install therubyracer -v '0.11.0'` succeeds before bundling.

实际上安装了gem ruby??racer,但版本是0.11.4.我只是不知道为什么它不采用这个版本并且只接受0.11.0.

另外如何安装0.11.0.当我运行错误“gem install therubyracer -v’0.11.0’”中给出的命令时,它无法执行并给出：

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

    /usr/local/bin/ruby extconf.rb
checking for main() in -lpthread... 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
--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=/usr/local/bin/ruby
--with-pthreadlib
--without-pthreadlib
--enable-debug
--disable-debug
/usr/local/lib/ruby/gems/1.9.1/gems/therubyracer-0.11.0/ext/v8/build.rb:50:in    `build_with_rubygem_libv8': undefined local variable or method `libv8_include_flags' for    main:Object (NameError)
from extconf.rb:20:in `<main>'


Gem files will remain installed in /usr/local/lib/ruby/gems/1.9.1/gems/therubyracer-    0.11.0 for inspection.
Results logged to /usr/local/lib/ruby/gems/1.9.1/gems/therubyracer-0.11.0/ext/v8/gem_make.out

这里有人可以帮忙吗？在堆栈和git上搜索了很多但是没有一个给定的解决方案工作.

我的gemfile：

source 'https://rubygems.org'

gem 'rails','3.2.12'
gem "paperclip"
gem 'mysql2'
gem "devise"
group :assets do
 gem 'sass-rails','~> 3.2.3'
 gem 'coffee-rails','~> 3.2.1'

gem 'uglifier','>= 1.0.3'
end


gem 'jquery-rails'
gem 'libv8','3.11.8.4',:platform => :ruby
gem 'therubyracer','0.11.0',:platforms => :ruby
gem 'rails_admin'
gem 'unicorn'
gem 'delayed_job_active_record'
gem 'daemons'