Description of problem:
ruby -r rbconfig -e "print RbConfig::CONFIG['ruby_version']"
 prints nothing with ruby-2.0. It prints '1.9.1' with F18 ruby.

Version-Release number of selected component (if applicable):
ruby-2.0.0.0-6.fc19.x86_64

How reproducible:
always

Steps to Reproduce:
1. ruby -r rbconfig -e "print RbConfig::CONFIG['ruby_version']"
2.
3.
  
Actual results:
no output

Expected results:
2.0.0

Additional info:
This breaks p.e. the latest vim from f19 git. autoconf tries to figure out the ruby libraries and versions and ends up with this:
 -DDYNAMIC_RUBY_DLL=\"libruby.so.2.0.0\" -DDYNAMIC_RUBY_VER= -I/usr/include

This should be 
 -DDYNAMIC_RUBY_DLL=\"libruby.so.2.0.0\" -DDYNAMIC_RUBY_VER=20 -I/usr/include