ruby on rails - gem install psych error -

ruby on rails - gem install psych error -

i'm trying bundle install rails project i'm stuck... when seek run gem install psych this:

building native extensions. take while... error: error installing psych: error: failed build gem native extension. /users/gibatronic/.rvm/rubies/ruby-1.9.3-p327/bin/ruby extconf.rb checking yaml.h... no yaml.h missing. seek 'port install libyaml +universal' or 'yum install libyaml-devel' *** extconf.rb failed *** not create makefile due reason, lack of necessary libraries and/or headers. check mkmf.log file more details. 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=/users/gibatronic/.rvm/rubies/ruby-1.9.3-p327/bin/ruby --with-libyaml-dir --without-libyaml-dir --with-libyaml-include --without-libyaml-include=${libyaml-dir}/include --with-libyaml-lib --without-libyaml-lib=${libyaml-dir}/lib gem files remain installed in /users/gibatronic/.rvm/gems/ruby-1.9.3-p327/gems/psych-1.3.4 inspection. results logged /users/gibatronic/.rvm/gems/ruby-1.9.3-p327/gems/psych-1.3.4/ext/psych/gem_make.out

i'm running ruby 1.9.3p327 rails 3.2.12 on os x 10.8.2

i've installed libyaml 0.1.4 rvm pkg install libyaml

i don't know anymore!

install libyaml

port install libyaml +universal

ruby-on-rails psych