Install Ruby 2.0.0 preview with rbenv on

gistfile1.sh

$ xcodebuild -version
Xcode 4.5.2
Build version 4G2008a

$ sw_vers
ProductName:	Mac OS X
ProductVersion:	10.8.2
BuildVersion:	12C60

$ brew install openssl
==> Downloading http://openssl.org/source/openssl-1.0.1c.tar.gz
######################################################################## 100.0%
==> perl ./Configure --prefix=/usr/local/Cellar/openssl/1.0.1c --openssldir=/usr/local/etc/openssl z
==> make
==> make test
==> make install MANDIR=/usr/local/Cellar/openssl/1.0.1c/share/man MANSUFFIX=ssl
==> Caveats
This formula is keg-only: so it was not symlinked into /usr/local.

Mac OS X already provides this software and installing another version in
parallel can cause all kinds of trouble.

The OpenSSL provided by OS X is too old for some software.

Generally there are no consequences of this for you. If you build your
own software and it requires this formula, you'll need to add to your
build variables:

    LDFLAGS:  -L/usr/local/opt/openssl/lib
    CPPFLAGS: -I/usr/local/opt/openssl/include

==> Summary
/usr/local/Cellar/openssl/1.0.1c: 428 files, 15M, built in 4.7 minutes

$ export CC=clang 
$ export CONFIGURE_OPTS=--with-openssl-dir=`brew --prefix openssl` 
$ rbenv install 2.0.0-preview1
$ rbenv rehash
$ rbenv shell 2.0.0-preview1
$ gem install bundler