关于Ruby Gem在Windows下安装，遇到编译有关问题的解决思路
转自:http://hi.baidu.com/kenrome/blog/item/d3803da859b485a7ca130c05.html
往往许多gem都是提供的源代码，当安装当本地时候会进行编译的过程。所以在Windows系统下，就经常遇到gem编译失败而导致安装的不成功。
我最近遇到就有安装 Hpricot, PageRankr两个gem的问题。
首先说一下Hpricot
在运行： gem install hpricot
的时候，发生编译问题。然后试：
gem install hpricot --platform=mswin32
安装成功，这个问题就在于，gem源没有选择mswin32.
但是安装PageRank就没那么幸运了，遇到都是编译的问题，解决办法是参照：http://*.com/questions/1718500/installing-hpricot-on-ruby-1-9-1-on-windows 中提到的，下载DevKit rubyinstaller.org/downloads 提供的mingw环境安装。
安装Hpricot的错误代码：
Administrator@MOVEPC ~/Documents/NetBeansProjects/WebSpiderCode (master)
$ gem install hpricot
Building native extensions. This could take a while...
ERROR: Error installing hpricot:
ERROR: Failed to build gem native extension.
c:/Ruby187/bin/ruby.exe extconf.rb
checking for stdio.h... 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
--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:/Ruby187/bin/ruby
Gem files will remain installed in c:/Ruby187/lib/ruby/gems/1.8/gems/hpricot-0.8.4 for inspection.
Results logged to c:/Ruby187/lib/ruby/gems/1.8/gems/hpricot-0.8.4/ext/fast_xs/gem_make.out
Administrator@MOVEPC ~/Documents/NetBeansProjects/WebSpiderCode (master)
$ gem install hpricot --platform=mswin32
Fetching: hpricot-0.8.4-i386-mswin32.gem (100%)
Successfully installed hpricot-0.8.4-x86-mswin32
1 gem installed
Installing ri documentation for hpricot-0.8.4-x86-mswin32...
Installing RDoc documentation for hpricot-0.8.4-x86-mswin32...
Administrator@MOVEPC ~/Documents/NetBeansProjects/WebSpiderCode (master)