$ git clone git://github.com/evanphx/rubinius.git
$ cd rubinius
$ ./configure --enable-llvm --skip-system
Configuring LLVM...
  Checking for existing LLVM tree: not found.
  Checking for prebuilt LLVM build...
    [ 100% (8259176 of 8259176) ]: done!
   No MD5 checksum for llvm-x86_64-unknown-linux-gnu.tar.bz2 available on server.
   Using LLVM library without checksum validation.
    Prebuilt packages updated.
  Unpacking prebuilt LLVM for x86_64-unknown-linux-gnu: done!

Checking for function 'backtrace': found!

Configured. Run 'rake' to build and run VM tests and rubyspecs
$ rake build
…
/bin/sh ./libtool --tag=CC   --mode=compile gcc -DHAVE_CONFIG_H -I. -I. -I/usr/local/include    -g -O2 -MT regerror.lo -MD -MP -MF .deps/regerror.Tpo -c -o regerror.lo regerror.c
libtool: Version mismatch error.  This is libtool 2.2.4, but the
libtool: definition of this LT_INIT comes from libtool 2.2.6.
libtool: You should recreate aclocal.m4 with macros from libtool 2.2.4
libtool: and run autoconf again.
make[2]: *** [regerror.lo] Error 63
make[2]: Leaving directory `/home/radek/src/rubinius/rubinius/vm/external_libs/onig'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/home/radek/src/rubinius/rubinius/vm/external_libs/onig'
make: *** [all] Error 2
rake aborted!
Command failed with status (2): [cd vm/external_libs/onig; ./configure && m...]