#
$ CONFIGURE_OPTS="--with-readline-dir=`brew --prefix readline` --with-openssl-dir=`brew --prefix openssl` --with-iconv-dir=`brew --prefix libiconv`" rbenv install 2.1.0
#
$ CONFIGURE_OPTS="--with-readline-dir=`brew --prefix readline` --with-openssl-dir=`brew --prefix openssl` --with-iconv-dir=`brew --prefix libiconv`" rbenv install 2.1.0