Having troubles with installing ImageMagick on Maverick 10.9.3 - ruby-on-rails

Question

The last two days I am fighting with configuration of ImageMagick and rmagick gem. I found several topics on SO, but none of them helped me out with this issue.
Recently, I've tried update also rvm, but it didn't help me neither. When I run now bundle update, the output is:
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
/Users/adam/.rvm/rubies/ruby-2.0.0-p353/bin/ruby extconf.rb
checking for Ruby version >= 1.8.5... yes
checking for /usr/bin/clang... 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 6.8.6 Q8 is installed in /usr/local
/opt/ImageMagick/bin/Magick-config reports version 6.8.8 Q16 is installed in /opt/ImageMagick
Using 6.8.6 Q8 from /usr/local.
checking for ImageMagick version >= 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
--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/adam/.rvm/rubies/ruby-2.0.0-p353/bin/ruby
/Users/adam/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/mkmf.rb:434:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
from /Users/adam/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/mkmf.rb:565:in `try_cpp'
from /Users/adam/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/mkmf.rb:1044:in `block in have_header'
from /Users/adam/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/mkmf.rb:895:in `block in checking_for'
from /Users/adam/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/mkmf.rb:340:in `block (2 levels) in postpone'
from /Users/adam/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/mkmf.rb:310:in `open'
from /Users/adam/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/mkmf.rb:340:in `block in postpone'
from /Users/adam/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/mkmf.rb:310:in `open'
from /Users/adam/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/mkmf.rb:336:in `postpone'
from /Users/adam/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/mkmf.rb:894:in `checking_for'
from /Users/adam/.rvm/rubies/ruby-2.0.0-p353/lib/ruby/2.0.0/mkmf.rb:1043:in `have_header'
from extconf.rb:194:in `<main>'
extconf failed, exit code 1
Gem files will remain installed in /Users/adam/.rvm/gems/ruby-2.0.0-p353/gems/rmagick-2.13.2 for inspection.
Results logged to /Users/adam/.rvm/gems/ruby-2.0.0-p353/extensions/x86_64-darwin-13/2.0.0/rmagick-2.13.2/gem_make.out
An error occurred while installing rmagick (2.13.2), and Bundler cannot continue.
Make sure that `gem install rmagick -v '2.13.2'` succeeds before bundling.
How to proceed now - which ImageMagick to remove? Or, is there something else what am I overlooking?

Answer 1

The error hints at the problem:
Warning: Found more than one ImageMagick installation. This could
cause problems at runtime.
/usr/local/bin/Magick-config reports version 6.8.6 Q8 is installed in /usr/local
/opt/ImageMagick/bin/Magick-config reports version 6.8.8 Q16 is installed in /opt/ImageMagick Using 6.8.6 Q8 from /usr/local.
And also:
You have to install development tools first.
You can do this by entering the command xcode-select --install and clicking Install
This installs gcc among other things you need to compile ImageMagick and other sources.
Now remove one of your current installations of ImageMagick. Or remove both and install ImageMagick with homebrew:
brew update
brew install imagemagick
If that doesn't work here's some links I found that might help:
ImageMagick Installer: http://cactuslab.com/imagemagick/
Link