环境大概是这样的：

max os 10.10.

rvm 1.26.3

使用 rvm 安装的 ruby 2.1.5

然后我想安装 mysql2gem 包：

gem install mysql2

报以下错误：

Building native extensions. This could take a while...

ERROR: Error installing mysql2:

ERROR: Failed to build gem native extension.

/Users/wjf/.rvm/rubies/ruby-2.1.5/bin/ruby -r ./siteconf20141206-1263-1pbvydq.rb 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... no

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.

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/wjf/.rvm/rubies/ruby-2.1.5/bin/ruby

--with-mysql-dir

--without-mysql-dir

--with-mysql-include

--without-mysql-include=${mysql-dir}/include

--with-mysql-lib

--without-mysql-lib=${mysql-dir}/lib

--with-mysql-config

--without-mysql-config

--with-mysql-dir

--without-mysql-dir

--with-mysql-include

--without-mysql-include=${mysql-dir}/include

--with-mysql-lib

--without-mysql-lib=${mysql-dir}/lib

--with-mysqlclientlib

--without-mysqlclientlib

--with-mlib

--without-mlib

--with-mysqlclientlib

--without-mysqlclientlib

--with-zlib

--without-zlib

--with-mysqlclientlib

--without-mysqlclientlib

--with-socketlib

--without-socketlib

--with-mysqlclientlib

--without-mysqlclientlib

--with-nsllib

--without-nsllib

--with-mysqlclientlib

--without-mysqlclientlib

--with-mygcclib

--without-mygcclib

--with-mysqlclientlib

--without-mysqlclientlib

extconf failed, exit code 1

Gem files will remain installed in /Users/wjf/.rvm/gems/ruby-2.1.5/gems/mysql2-0.3.17 for inspection.

Results logged to /Users/wjf/.rvm/gems/ruby-2.1.5/extensions/x86_64-darwin-14/2.1.0/mysql2-0.3.17/gem_make.out

wjfdeMBP:~ wjf$ rvm -v

Warning! PATH is not properly set up, '/Users/wjf/.rvm/gems/ruby-2.1.5/bin' is not at first place,

usually this is caused by shell initialization files - check them for 'PATH=...' entries,

it might also help to re-add RVM to your dotfiles: 'rvm get stable --auto-dotfiles',

to fix temporarily in this shell session run: 'rvm use ruby-2.1.5'.

以上错误在 windows/linux 平台上安装 mysql2gem 包的时候也很常见，网上的大部分解决方法都是安装 mysql 数据库及相关的 package,我在 linux 上就是这么解决的，但是现在在 mac 上我不想安装 mysql 数据库，就想搞定这个问题该怎么办？

我在 mysql2 在 github 的主页上看到这样一段：

This gem links against MySQL's libmysqlclient C shared library. You may need to install a package such as libmysqlclient-dev, mysql-devel, or other appropriate package for your system.

于是我开始尝试安装那两个 package,可是都安装失败，网上搜了半天也没有合适的方法，特来此求救！