gherkin looks for mkmf in the wrong folder

[mcandre]

When I try to install cucumber or its dependency gherkin with RubyGems, it looks for mkmf.rb in the wrong folder, complaining it can't find it in 1.9.1/..., even though I'm using Ruby 2.0 and have ruby2.0-dev installed.

As a workaround, I can install ruby1.9.1-dev.

System:

$ specs ruby rvm apt:ruby2.0-dev os
Specs:

specs 0.10
https://github.com/mcandre/specs#readme

bundle --version
Bundler version 1.6.2

gem --version
2.2.2

ruby --version
ruby 2.0.0p481 (2014-05-08 revision 45883) [x86_64-linux]

rvm --version

rvm 1.25.27 (stable) by Wayne E. Seguin <wayneeseguin@gmail.com>, Michal Papis <mpapis@gmail.com> [https://rvm.io/]


dpkg -l ruby2.0-dev
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name                                                  Version                                             Architecture Description
+++-=====================================================-===================================================-============-===============================================================================
ii  ruby2.0-dev:amd64                                     2.0.0.484-1ubuntu2                                  amd64        Header files for compiling extension modules for the Ruby 2.0

lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 14.04.1 LTS
Release:    14.04
Codename:   trusty