我已经尝试查看这些回答，但似乎没有任何作用。以下是错误信息。
funk@funktop ~/rails_projects/hearingtracker $ gem install debugger -v '1.6.8'
Fetching: columnize-0.8.9.gem (100%)
Successfully installed columnize-0.8.9
Fetching: debugger-ruby_core_source-1.3.5.gem (100%)
Successfully installed debugger-ruby_core_source-1.3.5
Fetching: debugger-linecache-1.2.0.gem (100%)
Successfully installed debugger-linecache-1.2.0
Fetching: debugger-1.6.8.gem (100%)
Building native extensions. This could take a while...
ERROR: Error installing debugger:
ERROR: Failed to build gem native extension.
/home/funk/.rvm/rubies/ruby-2.1.2/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=/home/funk/.rvm/rubies/ruby-2.1.2/bin/ruby
/home/funk/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/fileutils.rb:1573:in `stat': No such file or directory @ rb_file_s_stat - ./212/ruby_debug.h (Errno::ENOENT)
from /home/funk/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/fileutils.rb:1573:in `block in fu_each_src_dest'
from /home/funk/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/fileutils.rb:1587:in `fu_each_src_dest0'
from /home/funk/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/fileutils.rb:1571:in `fu_each_src_dest'
from /home/funk/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/fileutils.rb:399:in `cp'
from extconf.rb:83:in `block in <main>'
from extconf.rb:82:in `each'
from extconf.rb:82:in `<main>'
extconf failed, exit code 1
Gem files will remain installed in /home/funk/.rvm/gems/ruby-2.1.2/gems/debugger-1.6.8 for inspection.
Results logged to /home/funk/.rvm/gems/ruby-2.1.2/extensions/x86_64-linux/2.1.0/debugger-1.6.8/gem_make.out