I need version 1.0.1 of debugger-linecache for a project, and I am facing the following error when trying to install. trunk ☺ gem install debugger-linecache -v '1.0.1' Building native extensions. This could take a while... ERROR: Error installing debugger-linecache: ERROR: Failed to build gem native extension. /Users/jordanscales/.rvm/rubies/ruby-1.9.3-p194/bin/ruby extconf.rb checking for vm_core