ubuntu 12.04 ruby 2.1 rvm Ruby/Tk 動かない
http://futurismo.biz/archives/2226
$ sudo apt-get remove tk-dev
$ sudo apt-get install tk8.4-dev tcl8.4-dev
$ sudo ln -sfn /usr/lib/tcl8.4/tclConfig.sh /usr/lib/tclConfig.sh
$ sudo ln -sfn /usr/lib/tk8.4/tkConfig.sh /usr/lib/tkConfig.sh
$ rvm reinstall ruby-2.1.2