需要必要的库和或头文件时如何安装 ruby​​debug

我的Rails是3.2.1.4，Ruby是1.9.3p448.

我安装ruby-debug时出错:

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

    /home/hxh/.rvm/rubies/ruby-1.9.3-p448/bin/ruby extconf.rb
Can't handle 1.9.x yet
*** 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/hxh/.rvm/rubies/ruby-1.9.3-p448/bin/ruby


Gem files will remain installed in /home/hxh/.rvm/gems/ruby-1.9.3-p448/gems/linecache-0.46 for inspection.
Results logged to /home/hxh/.rvm/gems/ruby-1.9.3-p448/gems/linecache-0.46/ext/gem_make.out

谁能告诉我错误在哪里？