环境：ruby 1.9.3, osx 10.8.1, xcode 4.4.1 CLTool, , mysql 5.5.27 dmg 安装 启动正常

gem install mysql2

Building native extensions. This could take a while... ERROR: Error installing mysql2: ERROR: Failed to build gem native extension.

/Users/sandy/.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 client.c:1: In file included from ./mysql2_ext.h:8: In file included from /Users/sandy/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/ruby.h:32: /Users/sandy/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/ruby/ruby.h:105:37: error: 'ruby_check_sizeof_long' declared as an array with a negative size typedef char ruby_check_sizeof_long[SIZEOF_LONG == sizeof(long) ? 1 : -1]; ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /Users/sandy/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/x86_64-darwin12.0.0/ruby/config.h:24:21: note: expanded from macro 'SIZEOF_LONG' #define SIZEOF_LONG 8 ^ In file included from client.c:1: In file included from ./mysql2_ext.h:8: In file included from /Users/sandy/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/ruby.h:32: /Users/sandy/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/ruby/ruby.h:109:38: error: 'ruby_check_sizeof_voidp' declared as an array with a negative size typedef char ruby_check_sizeof_voidp[SIZEOF_VOIDP == sizeof(void*) ? 1 : -1]; ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /Users/sandy/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/x86_64-darwin12.0.0/ruby/config.h:28:22: note: expanded from macro 'SIZEOF_VOIDP' #define SIZEOF_VOIDP 8 ^ In file included from client.c:1: In file included from ./mysql2_ext.h:8: In file included from /Users/sandy/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/ruby.h:32: In file included from /Users/sandy/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/ruby/ruby.h:1382: In file included from /Users/sandy/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/ruby/intern.h:34: /Users/sandy/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/ruby/st.h:67:45: error: 'st_check_for_sizeof_st_index_t' declared as an array with a negative size typedef char st_check_for_sizeof_st_index_t[SIZEOF_VOIDP == (int)sizeof(st_index_t) ? 1 : -1]; ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /Users/sandy/.rvm/rubies/ruby-1.9.3-p194/include/ruby-1.9.1/x86_64-darwin12.0.0/ruby/config.h:28:22: note: expanded from macro 'SIZEOF_VOIDP' #define SIZEOF_VOIDP 8 ^ 3 errors generated. make: *** [client.o] Error 1

Gem files will remain installed in /Users/sandy/.rvm/gems/ruby-1.9.3-p194/gems/mysql2-0.3.11 for inspection. Results logged to /Users/sandy/.rvm/gems/ruby-1.9.3-p194/gems/mysql2-0.3.11/ext/mysql2/gem_make.out