The vim that ships with 10.8 (and IIRC 10.7, maybe 10.6) has ruby and python linked out of the box, and straight-up

    ./configure --enable-rubyinterp && make

works just fine on my machine.

Or if yours isn't for whatever reason, you could cheat and grab MacVim[0] then symlink `/Applications/MacVim.app/Contents/MacOS/Vim` to `/usr/local/bin/vim` (editing paths as necessary)

[0] https://github.com/b4winckler/macvim