问试图安装therubyracer时出错

EN

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

        /opt/ruby-enterprise-1.8.7-2012.02/bin/ruby extconf.rb
checking for main() in -lpthread... yes
Warning! Unable to load libv8 ~> 3.16.14.
*** 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=/opt/ruby-enterprise-1.8.7-2012.02/bin/ruby
    --with-pthreadlib
    --without-pthreadlib
    --enable-debug
    --disable-debug
/opt/ruby-enterprise-1.8.7-2012.02/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:36:in `gem_original_require': no such file to load -- libv8 (LoadError)
    from /opt/ruby-enterprise-1.8.7-2012.02/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:36:in `require'
    from extconf.rb:29

Gem files will remain installed in /home/speedup18meses/.gems/gems/therubyracer-0.12.1 for inspection.
Results logged to /home/speedup18meses/.gems/gems/therubyracer-0.12.1/ext/v8/gem_make.out

gem install libv8 -v '3.16.14.3' -- --with-system-v8
gem install therubyracer

gem install libv8
gem install therubyracer