gem install mysql2 failed but you could replace mysql with mariadb first

緣由

環境：Mac 10.7 and 10.8

欲安裝/更新 gem mysql2

錯誤訊息

Fetching: mysql2-0.3.13.gem (100%)
Building native extensions.  This could take a while...
ERROR:  Error installing mysql2:
    ERROR: Failed to build gem native extension.

    /Users/pct/.rvm/rubies/ruby-2.0.0-p247/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/pct/.rvm/rubies/ruby-2.0.0-p247/bin/ruby
    --with-mysql-config
    --without-mysql-config

偷懶解決方式

$ brew remove mysql
$ brew install mariadb
$ gem install mysql2

實際解決方式？

還沒測，但就趁機換 mariadb 了 :)