Can't run rails server after trying to install Rmagick - ruby-on-rails

Question

I'm on windows and I downloaded and installed rmagick-win32 RMagick-2.12.0-ImageMagick-6.5.6-8-Q8 from here (http://rubyforge.org/frs/?group_id=12&release_id=42049) which I unzipped and installed using 'gem install rmagick'
When I try to run rails s, I get this error message
C:\Users\Me\Desktop\sample_app>rails s
←[31mCould not find gem 'rmagick (>= 0) x86-mingw32' in any of the gem sources l
isted in your Gemfile.←[0m
←[33mRun `bundle install` to install missing gems.←[0m
So I try to bundle install or bundle update then I get this (I took out the full list of gems to save space):
C:\Users\Me\Desktop\sample_app>bundle update
Fetching source index for https://rubygems.org/
Installing rmagick (2.13.2) with native extensions
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension
.
C:/RailsInstaller/Ruby1.9.3/bin/ruby.exe extconf.rb
checking for Ruby version >= 1.8.5... 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=C:/RailsInstaller/Ruby1.9.3/bin/ruby
C:/RailsInstaller/Ruby1.9.3/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 C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/mkmf.rb:506:in `try_cpp'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/mkmf.rb:931:in `block in
have_header'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/mkmf.rb:790:in `block in
checking_for'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/mkmf.rb:284:in `block (2
levels) in postpone'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/mkmf.rb:254:in `open'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/mkmf.rb:284:in `block in
postpone'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/mkmf.rb:254:in `open'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/mkmf.rb:280:in `postpone
'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/mkmf.rb:789:in `checking
_for'
from C:/RailsInstaller/Ruby1.9.3/lib/ruby/1.9.1/mkmf.rb:930:in `have_hea
der'
from extconf.rb:194:in `<main>'
Gem files will remain installed in C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9
.1/gems/rmagick-2.13.2 for inspection.
Results logged to C:/RailsInstaller/Ruby1.9.3/lib/ruby/gems/1.9.1/gems/rmagick-2
.13.2/ext/RMagick/gem_make.out
An error occured while installing rmagick (2.13.2), and Bundler cannot continue.
Make sure that `gem install rmagick -v '2.13.2'` succeeds before bundling.
Then I downloaded rmagick 2.13.2 and put it into the same folder and ran "gem install rmagick -v '2.13.2' but I'm getting a failed ERROR: Failed to build gem native extension again
I am trying to get 2.13.2 installed but I can't find any information on this. Anyone know if that's the issue and how this can be fixed?

Answer 1

On Windows, you need the DevKit for Ruby to compile native C extensions (which some gems have included).