CentOS: mysql2 gem の install でこけるときの解決法

Rails の Gemfile に mysql2 を指定していたら以下のエラーを発して bundle install がこけた.

Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    /var/lib/jenkins/.rvm/rubies/ruby-2.1.0/bin/ruby extconf.rb 
checking for ruby/thread.h... yes
checking for rb_thread_call_without_gvl() in ruby/thread.h... yes
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_query() in -lmysqlclient... no
checking for main() in -lm... yes
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lz... yes
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lsocket... no
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lnsl... yes
checking for mysql_query() in -lmysqlclient... no
checking for main() in -lmygcc... no
checking for mysql_query() in -lmysqlclient... no
*** 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.

解決法

mysql-devel をインストールしておく.

sudo yum install mysql-devel

References

mysql - Error installing mysql2: Failed to build gem native extension - Stack Overflow