title: RVM error while running make install. Error comes while installing power_assert gem
body: <p>Im trying to install ruby 2.2.2 in my arch machine. When I run rvm install, I get the following error. Tried several times. Even removed rvm and re-installed. Still the same issue.</p>
  
  <pre><code>○  rvm install 2.2.2
  Searching for binary rubies, this might take some time.
  No binary rubies available for: arch/libc-2.21/x86_64/ruby-2.2.2.
  Continuing with compilation. Please read 'rvm help mount' to get more information on binary rubies.
  Checking requirements for arch.
  Requirements installation successful.
  Installing Ruby from source to: /home/pubudu/.rvm/rubies/ruby-2.2.2, this may take a while depending on your cpu(s)...
  ruby-2.2.2 - #downloading ruby-2.2.2, this may take a while depending on your connection...
    % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                               Dload  Upload   Total   Spent    Left  Speed
  100 12.6M  100 12.6M    0     0   323k      0  0:00:40  0:00:40 --:--:--  340k
  No checksum for downloaded archive, recording checksum in user configuration.
  ruby-2.2.2 - #extracting ruby-2.2.2 to /home/pubudu/.rvm/src/ruby-2.2.2 - please wait
  ruby-2.2.2 - #configuring - please wait
  ruby-2.2.2 - #post-configuration - please wait
  ruby-2.2.2 - #compiling - please wait
  ruby-2.2.2 - #installing - please wait
  Error running '__rvm_make install',
  showing last 15 lines of /home/pubudu/.rvm/log/1429407987_ruby-2.2.2/install.log
                            rake 10.4.2
                            rdoc 4.2.0
  installing bundle gems:       /home/pubudu/.rvm/rubies/ruby-2.2.2/lib/ruby/gems/2.2.0 (build_info, cache, doc, extensions, gems, specifications)
                            test-unit-3.0.8.gem
                            minitest-5.4.3.gem
                            power_assert-0.2.2.gem
  ./tool/rbinstall.rb:728:in `chmod': Operation not permitted @ chmod_internal - / (Errno::EPERM)
      from ./tool/rbinstall.rb:728:in `block in &lt;main&gt;'
      from ./tool/rbinstall.rb:757:in `call'
      from ./tool/rbinstall.rb:757:in `block in &lt;main&gt;'
      from ./tool/rbinstall.rb:754:in `each'
      from ./tool/rbinstall.rb:754:in `&lt;main&gt;'
  uncommon.mk:253: recipe for target 'do-install-nodoc' failed
  make: *** [do-install-nodoc] Error 1
  +__rvm_make:0&gt; return 2
  There has been an error while running make install. Halting the installation.
  </code></pre>