Ошибка при установке gruff gem в windows8

Question

Я получил ошибку при установке gem gruff

> C:\DevKit>gem install gruff --source http://rubygems.org
> --platform=ruby Building native extensions.  This could take a while... ERROR:  Error installing gruff:
>         ERROR: Failed to build gem native extension.
> 
>     C:/Ruby200/bin/ruby.exe 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=C:/Ruby200/bin/ruby extconf.rb:141:in ``': No such file or directory - identify -version (Errno::ENO ENT)
>         from extconf.rb:141:in `configure_compile_options'
>         from extconf.rb:16:in `initialize'
>         from extconf.rb:548:in `new'
>         from extconf.rb:548:in `<main>'
> 
> 
> Gem files will remain installed in
> C:/Ruby200/lib/ruby/gems/2.0.0/gems/rmagick-2 .16.0 for inspection.
> Results logged to
> C:/Ruby200/lib/ruby/gems/2.0.0/gems/rmagick-2.16.0/ext/RMagick
> /gem_make.out

RubyVersion => ruby ​​2.0.0p353