Can't install Nokogiri 1.4.3 gem

Can't install nokogiri 1.4.3 gem. Nokogiri 1.6.6.2 installs without a problem. Using latest RVM on Ubuntu.

pm@sniegas:~$ gem install nokogiri -v '1.4.3'
Fetching: nokogiri-1.4.3.gem (100%)
Building native extensions.  This could take a while...
ERROR:  Error installing nokogiri:
    ERROR: Failed to build gem native extension.

    /home/pm/.rvm/rubies/ruby-2.2.1/bin/ruby -r ./siteconf20150519-7580-2yzgsg.rb extconf.rb
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Provided configuration options:
    --with-opt-dir
    --without-opt-dir
    --with-opt-include
    --without-opt-include=${opt-dir}/include
    --with-opt-lib
    --without-opt-lib=${opt-dir}/lib
    --with-make-prog
    --without-make-prog
    --srcdir=.
    --curdir
    --ruby=/home/pm/.rvm/rubies/ruby-2.2.1/bin/$(RUBY_BASE_NAME)
extconf.rb:10:in `<main>': uninitialized constant Config (NameError)

extconf failed, exit code 1

Gem files will remain installed in /home/pm/.rvm/gems/ruby-2.2.1/gems/nokogiri-1.4.3 for inspection.
Results logged to /home/pm/.rvm/gems/ruby-2.2.1/extensions/x86_64-linux/2.2.0/nokogiri-1.4.3/gem_make.out

Where should I start to look for a solution?

I managed to get 1.4.7 to install by doing (close to) the following:

git clone git@github.com:sparklemotion/nokogiri.git
cd nokogiri
gem install rake-compiler hoe racc rexical
git checkout v1.4.7 # 1.4.3 in your case
# edit ./ext/nokogiri/extconf.rb and replace `Config` with `RbConfig`
rake install_deps
rake install_gem

Hopefully I didn't forget a step.

Edit: Scratch that, the installed gem doesn't work. I'm going to leave this here for now in case it helps someone.

Edit (Jonas): Hint for the solution is in a bug report. I stick with Ruby 2.1.5 and it solved this issue.