title: RMagick gem fails to install on Debian Stable
body: <p>edit:[FIXED]
  The problem was that I had it installed already, but didn't know, and tried to install from source. This created two versions and the gem didn't know which to use. I fixed it by going to the downloaded source and running</p>
  
  <pre><code>sudo make uninstall
  </code></pre>
  
  <p>Then I ran gem install rmagick again and it worked!</p>
  
  <p>[ORIGINAL PROBLEM]</p>
  
  <p>I'm trying to install the rmagick gem like in <a href="http://railscasts.com/episodes/253-carrierwave-file-uploads" rel="noreferrer">this railscast</a>. Here's a snippet of what I put in my gemfile:</p>
  
  <pre><code> gem 'rmagick'
   gem 'carrierwave'
  </code></pre>
  
  <p>And when I run bundle install I get the following output:</p>
  
  <pre><code>Installing rmagick (2.13.1) with native extensions 
  Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.
  
          /home/techusb/.rbenv/versions/1.9.3-p125/bin/ruby extconf.rb 
  checking for Ruby version &gt;= 1.8.5... yes
  extconf.rb:128: Use RbConfig instead of obsolete and deprecated Config.
  checking for cc... yes
  checking for Magick-config... yes
  
  Warning: Found more than one ImageMagick installation. This could cause problems at runtime.
           /usr/local/bin/Magick-config reports version 6.8.0 Q16 is installed in /usr/local
           /usr/bin/Magick-config reports version 1.3.12 is installed in /usr
  Using 6.8.0 Q16 from /usr/local.
  
  checking for ImageMagick version &gt;= 6.4.9... yes
  checking for HDRI disabled version of ImageMagick... yes
  checking for stdint.h... *** 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/techusb/.rbenv/versions/1.9.3-p125/bin/ruby
  /home/techusb/.rbenv/versions/1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:381:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
  You have to install development tools first.
      from /home/techusb/.rbenv/versions/1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:506:in `try_cpp'
      from /home/techusb/.rbenv/versions/1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:931:in `block in have_header'
      from /home/techusb/.rbenv/versions/1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:790:in `block in checking_for'
      from /home/techusb/.rbenv/versions/1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:284:in `block (2 levels) in postpone'
      from /home/techusb/.rbenv/versions/1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:254:in `open'
      from /home/techusb/.rbenv/versions/1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:284:in `block in postpone'
      from /home/techusb/.rbenv/versions/1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:254:in `open'
      from /home/techusb/.rbenv/versions/1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:280:in `postpone'
      from /home/techusb/.rbenv/versions/1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:789:in `checking_for'
      from /home/techusb/.rbenv/versions/1.9.3-p125/lib/ruby/1.9.1/mkmf.rb:930:in `have_header'
      from extconf.rb:193:in `&lt;main&gt;'
  
  
  Gem files will remain installed in /home/techusb/.rbenv/versions/1.9.3-p125/lib/ruby/gems/1.9.1/gems/rmagick-2.13.1 for inspection.
  Results logged to /home/techusb/.rbenv/versions/1.9.3-p125/lib/ruby/gems/1.9.1/gems/rmagick-2.13.1/ext/RMagick/gem_make.out
  An error occurred while installing rmagick (2.13.1), and Bundler cannot continue.
  Make sure that `gem install rmagick -v '2.13.1'` succeeds before bundling.
  </code></pre>
  
  <p>Regarding this line:</p>
  
  <pre><code>The compiler failed to generate an executable file. (RuntimeError)
  You have to install development tools first.
  </code></pre>
  
  <p>I think I've exhausted all the information on how to fix this error via google/stackoverflow. I already tried installing the development packages and such. Not sure where to go from here. Any help greatly appreciated.</p>