Error trying to reinstall rugged gem - ruby-on-rails

Question

I'm trying to reinstall rugged as it's causing issues with another program (Dandelion Deploy).
I've recently updated my RVM and Ruby, and installed cmake and pkg-config again, but I get this error when I run the following command: gem install rugged
Fetching: rugged-0.22.2.gem (100%)
Building native extensions. This could take a while...
ERROR: Error installing rugged:
ERROR: Failed to build gem native extension.
/Users/J/.rvm/rubies/ruby-2.0.0-p645/bin/ruby -r ./siteconf20150605-56781-qfplzm.rb extconf.rb
checking for gmake... no
checking for make... yes
checking for cmake... yes
checking for pkg-config... yes
-- cmake .. -DBUILD_CLAR=OFF -DTHREADSAFE=ON -DBUILD_SHARED_LIBS=OFF -DCMAKE_C_FLAGS=-fPIC -DCMAKE_BUILD_TYPE=RelWithDebInfo -G "Unix Makefiles"
*** 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
--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=/Users/J/.rvm/rubies/ruby-2.0.0-p645/bin/ruby
--use-system-libraries
extconf.rb:13:in `sys': ERROR: 'cmake .. -DBUILD_CLAR=OFF -DTHREADSAFE=ON -DBUILD_SHARED_LIBS=OFF -DCMAKE_C_FLAGS=-fPIC -DCMAKE_BUILD_TYPE=RelWithDebInfo -G "Unix Makefiles"' failed (RuntimeError)
from extconf.rb:66:in `block (2 levels) in <main>'
from extconf.rb:65:in `chdir'
from extconf.rb:65:in `block in <main>'
from extconf.rb:62:in `chdir'
from extconf.rb:62:in `<main>'
extconf failed, exit code 1
Gem files will remain installed in /Users/J/.rvm/rubies/ruby-2.0.0-p645/lib/ruby/gems/2.0.0/gems/rugged-0.22.2 for inspection.
Results logged to /Users/J/.rvm/rubies/ruby-2.0.0-p645/lib/ruby/gems/2.0.0/extensions/x86_64-darwin-11/2.0.0/rugged-0.22.2/gem_make.out
I'm a frontender, so this is way out of my comfort zone. Any help appreciated!
Mac OSX 10.7.5, Lion

Answer 1

Solved it.
I installed the latest version of XCode I could (4.6.3) on OSX 10.7.5.
To get dandelion working, I installed the following gems: rugged, dandelion and net-sftp
and everything worked again.