问在此计算机上可用的gem中找不到gem 'mysql2 (>= 0) ruby

EN

    Installing mysql2 (0.3.13) 
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

    /Users/albert/.rvm/rubies/ruby-1.9.3-head/bin/ruby extconf.rb 
checking for rb_thread_blocking_region()... yes
checking for rb_wait_for_single_fd()... yes
checking for rb_hash_dup()... yes
checking for rb_intern3()... yes
checking for mysql.h... no
checking for mysql/mysql.h... no
-----
mysql.h is missing.  please check your installation of mysql and try again.
-----
*** 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/albert/.rvm/rubies/ruby-1.9.3-head/bin/ruby
    --with-mysql-config
    --without-mysql-config


Gem files will remain installed in /Users/albert/.rvm/gems/ruby-1.9.3-head@kyrgyz-tours/gems/mysql2-0.3.13 for inspection.
Results logged to /Users/albert/.rvm/gems/ruby-1.9.3-head@kyrgyz-tours/gems/mysql2-0.3.13/ext/mysql2/gem_make.out

An error occurred while installing mysql2 (0.3.13), and Bundler cannot continue.
Make sure that `gem install mysql2 -v '0.3.13'` succeeds before bundling.