ruby-1.9.3-p385 cumulative performance patch for rbenv
This installs a patched ruby 1.9.3-p385 with various performance improvements and a backported COW-friendly GC, all courtesy of funny-falcon.
You will also need a C Compiler. If you're on Linux, you probably already have one or know how to install one. On OS X, you should install XCode, and
brew install autoconf using homebrew.