这是来自〜/ .bashrc的PATH声明：
PATH=/usr/local/bin:$PATH:$HOME/.rvm/bin:/usr/local/MysqL/bin # Add RVM to PATH for scripting
符号链接：
Diego-Blantons-MacBook-Pro-3:~ lmrunner07$sudo ln -s /usr/bin/llvm-gcc-4.2 /usr/bin/gcc-4.2 Password:
尝试安装gem：
Diego-Blantons-MacBook-Pro-3:~ lmrunner07$gem install MysqL2 Building native extensions. This could take a while... ERROR: Error installing MysqL2: ERROR: Failed to build gem native extension. /Users/lmrunner07/.rvm/rubies/ruby-1.9.3-p194/bin/ruby extconf.rb checking for rb_thread_blocking_region()... yes checking for rb_wait_for_single_fd()... yes checking for MysqL.h... yes checking for errmsg.h... yes checking for MysqLd_error.h... yes creating Makefile make compiling client.c In file included from /Users/lmrunner07/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/ruby.h:32,from ./MysqL2_ext.h:8,from client.c:1: /Users/lmrunner07/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/ruby/ruby.h:105: error: size of array ‘ruby_check_sizeof_long’ is negative /Users/lmrunner07/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/ruby/ruby.h:109: error: size of array ‘ruby_check_sizeof_voidp’ is negative In file included from /Users/lmrunner07/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/ruby/intern.h:34,from /Users/lmrunner07/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/ruby/ruby.h:1382,from /Users/lmrunner07/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/ruby.h:32,from client.c:1: /Users/lmrunner07/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/ruby/st.h:67: error: size of array ‘st_check_for_sizeof_st_index_t’ is negative client.c: In function ‘rb_raise_MysqL2_error’: client.c:98: warning: ISO C90 forbids mixed declarations and code client.c: In function ‘rb_MysqL_client_socket’: client.c:590: warning: ISO C90 forbids mixed declarations and code make: *** [client.o] Error 1 Gem files will remain installed in /Users/lmrunner07/.rvm/gems/ruby-1.9.3-p194/gems/MysqL2-0.3.11 for inspection. Results logged to /Users/lmrunner07/.rvm/gems/ruby-1.9.3-p194/gems/MysqL2-0.3.11/ext/MysqL2/gem_make.out
我已经删除了自制软件安装的MysqL以及启动代理.另外rm -rf gem目录(Users / lmrunner07 / .rvm / gems / ruby-1.9.3-p194 / gems / MysqL2-0.3.11)
解决方法
>安装homebrew ruby<(curl -fsSk https://raw.github.com/mxcl/homebrew/go)
(查看他们的网站使用http://mxcl.github.com/homebrew/)
>按照这些说明http://robots.thoughtbot.com/post/27985816073/the-hitchhikers-guide-to-riding-a-mountain-lion
>用homebrew brew install MysqL重新安装MysqL. (我尝试按照这些说明http://erictarn.com/post/28269453881/how-i-installed-mysql-rvm-ruby-and-rails-on-mountain安装MysqL但我后来遇到了问题,所以我建议用自制软件重新安装MysqL.)
>重新安装rvm和rails以及我项目的宝石(包括MysqL2)
注意：当我尝试构建时,我遇到了库问题,未加载库：libMysqLclient.18.dylib,它是通过运行sudo ln -s /usr/local/MysqL/lib/libMysqLclient.18.dylib /usr/lib修复的/libMysqLclient.18.dylib(如果遇到同样的问题,请参阅Library not loaded: libmysqlclient.16.dylib error when trying to run ‘rails server’ on OS X 10.6 with mysql2 gem.)