我使用的操作系统是Windows XP, 安装了Ruby 1.9.2和Rails，并且已经安装了MySQL。但是当我尝试运行gem install mysql2（或bundle install）时，会出现错误：
C:\ruby\cred2>gem install mysql2
Building native extensions. This could take a while...
ERROR: Error installing mysql2:
ERROR: Failed to build gem native extension.
C:/Ruby192/bin/ruby.exe extconf.rb
checking for rb_thread_blocking_region()... *** 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
--without-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=C:/Ruby192/bin/ruby
C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:368:in `try_do': The complier failed to genera
te an executable file. (RuntimeError)
You have to install development tools first.
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:435:in `try_link0'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:440:in `try_link'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:552:in `try_func'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:797:in `block in have_func'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:693:in `block in checking_for'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:280:in `block (2 levels) in postp
one'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:254:in `open'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:280:in `block in postpone'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:254:in `open'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:276:in `postpone'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:692:in `checking_for'
from C:/Ruby192/lib/ruby/1.9.1/mkmf.rb:796:in `have_func'
from extconf.rb:9:in `<main>'
Gem files will remain installed in C:/Ruby192/lib/ruby/gems/1.9.1/gems/mysql2-0.
2.4 for inspection.
Results logged to C:/Ruby192/lib/ruby/gems/1.9.1/gems/mysql2-0.2.4/ext/mysql2/ge
m_make.out
C:\ruby\cred2>