build gem native extension. (Gem::Installer::ExtensionBuildError)

/usr/bin/ruby extconf.rb
checking for main() in -lc... yes
creating Makefile

make
gcc -I. -I/usr/include/ruby-1.9.1/i686-linux -I/usr/include/ruby-1.9.1/ruby/backward -I/usr/include/ruby-1.9.1 -I. -D_FILE_OFFSET_BITS=64  -fPIC -march=i686 -mtune=generic -O2 -pipe -fPIC -O0 -Wall -Werror  -o redcloth_attributes.o -c redcloth_attributes.c
ragel/redcloth_attributes.c.rl: In function ‘redcloth_attribute_parser’:
ragel/redcloth_attributes.c.rl:26:11: error: variable ‘act’ set but not used [-Werror=unused-but-set-variable]
cc1: all warnings being treated as errors

make: *** [redcloth_attributes.o] Error 1


Gem files will remain installed in /home/homer/.rvm/gems/ruby-1.9.2-p0/gems/RedCloth-4.2.7 for inspection.
Results logged to /home/homer/.rvm/gems/ruby-1.9.2-p0/gems/RedCloth-4.2.7/ext/redcloth_scan/gem_make.out
        from /usr/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:486:in `block in build_extensions'
        from /usr/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:446:in `each'
        from /usr/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:446:in `build_extensions'
        from /usr/lib/ruby/site_ruby/1.9.1/rubygems/installer.rb:198:in `install'
        from /home/homer/.rvm/gems/ruby-1.9.2-p0@global/gems/bundler-1.0.15/lib/bundler/source.rb:101:in `block in install'
        from /home/homer/.rvm/gems/ruby-1.9.2-p0@global/gems/bundler-1.0.15/lib/bundler/rubygems_integration.rb:78:in `preserve_paths'
        from /home/homer/.rvm/gems/ruby-1.9.2-p0@global/gems/bundler-1.0.15/lib/bundler/source.rb:91:in `install'
        from /home/homer/.rvm/gems/ruby-1.9.2-p0@global/gems/bundler-1.0.15/lib/bundler/installer.rb:58:in `block (2 levels) in run'
        from /home/homer/.rvm/gems/ruby-1.9.2-p0@global/gems/bundler-1.0.15/lib/bundler/rubygems_integration.rb:93:in `with_build_args'
        from /home/homer/.rvm/gems/ruby-1.9.2-p0@global/gems/bundler-1.0.15/lib/bundler/installer.rb:57:in `block in run'
        from /home/homer/.rvm/gems/ruby-1.9.2-p0@global/gems/bundler-1.0.15/lib/bundler/spec_set.rb:12:in `block in each'
        from /home/homer/.rvm/gems/ruby-1.9.2-p0@global/gems/bundler-1.0.15/lib/bundler/spec_set.rb:12:in `each'
        from /home/homer/.rvm/gems/ruby-1.9.2-p0@global/gems/bundler-1.0.15/lib/bundler/spec_set.rb:12:in `each'
        from /home/homer/.rvm/gems/ruby-1.9.2-p0@global/gems/bundler-1.0.15/lib/bundler/installer.rb:49:in `run'
        from /home/homer/.rvm/gems/ruby-1.9.2-p0@global/gems/bundler-1.0.15/lib/bundler/installer.rb:8:in `install'
        from /home/homer/.rvm/gems/ruby-1.9.2-p0@global/gems/bundler-1.0.15/lib/bundler/cli.rb:222:in `install'
        from /home/homer/.rvm/gems/ruby-1.9.2-p0@global/gems/bundler-1.0.15/lib/bundler/vendor/thor/task.rb:22:in `run'
        from /home/homer/.rvm/gems/ruby-1.9.2-p0@global/gems/bundler-1.0.15/lib/bundler/vendor/thor/invocation.rb:118:in `invoke_task'
        from /home/homer/.rvm/gems/ruby-1.9.2-p0@global/gems/bundler-1.0.15/lib/bundler/vendor/thor.rb:246:in `dispatch'
        from /home/homer/.rvm/gems/ruby-1.9.2-p0@global/gems/bundler-1.0.15/lib/bundler/vendor/thor/base.rb:389:in `start'
        from /home/homer/.rvm/gems/ruby-1.9.2-p0@global/gems/bundler-1.0.15/bin/bundle:13:in `<top (required)>'
        from /usr/bin/bundle:19:in `load'
        from /usr/bin/bundle:19:in `<main>'