As a non-ruby guy, I spent too much time figuring out... If you are getting this error while trying to launch Vim:
Vim: Caught deadly signal SEGV Vim: Finished. Segmentation fault: 11
Your Ruby system version does not match the one MacVim was used to compile. One of the options is use the same MacVim Ruby version to recompile command-t:
brew install ruby192 cd ~/.vim/bundle/command-t/ruby/command-t/ /usr/local/Cellar/ruby192/1.9.2-p320/bin/ruby extconf.rb /usr/local/Cellar/ruby192/1.9.2-p320/bin/rake make
This works for me, it might not for you.