Error installing Compass on Mac

I'm trying to install the compass on my machine and I run into the following error.

I'm using with command with sudo.

    Building native extensions.  This could take a while...
    ERROR:  Error installing compass:
    ERROR: Failed to build gem native extension.

    /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby -r      ./siteconf20140930-1189-279ned.rb extconf.rb
    checking for ffi.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=/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/bin/ruby
       --with-ffi_c-dir
       --without-ffi_c-dir
       --with-ffi_c-include
       --without-ffi_c-include=${ffi_c-dir}/include
       --with-ffi_c-lib
       --without-ffi_c-lib=${ffi_c-dir}/
       --with-libffi-config
       --without-libffi-config
       --with-pkg-config
       --without-pkg-config
     /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/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       /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/mkmf.rb:549:in 'block in try_compile'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/mkmf.rb:502:in 'with_werror'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/mkmf.rb:549:in 'try_compile'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/mkmf.rb:1044:in 'block in have_header'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/mkmf.rb:895:in 'block in checking_for'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/mkmf.rb:340:in 'block (2 levels) in postpone'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/mkmf.rb:310:in 'open'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/mkmf.rb:340:in 'block in postpone'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/mkmf.rb:310:in 'open'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/mkmf.rb:336:in 'postpone'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/mkmf.rb:894:in 'checking_for'
from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/mkmf.rb:1043:in 'have_header'
from extconf.rb:16:in '<main>'

extconf failed, exit code 1

Gem files will remain installed in /Library/Ruby/Gems/2.0.0/gems/ffi-1.9.5 for inspection.
Results logged to /Library/Ruby/Gems/2.0.0/extensions/universal-darwin-13/2.0.0/ffi-1.9.5/gem_make.out

Has anyone ever had the same error? Do you know how to solve it?