Ошибка установки отладчика-linecache

я пытаюсь установить гем отладчика-linecache, но я получил следующую ошибку,

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

        /usr/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
        --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/bin/ruby
extconf.rb:2:in `require': no such file to load -- debugger/ruby_core_source (LoadError)
        from extconf.rb:2


Gem files will remain installed in /usr/lib/ruby/gems/1.8/gems/debugger-linecache-1.1.1 for inspection.
Results logged to /usr/lib/ruby/gems/1.8/gems/debugger-linecache-1.1.1/ext/trace_nums/gem_make.out

я уже сделал:

sudo gem install debugger-ruby_core_source