gem安装patron的时候出现异常： Can't find libcurl or curl/curl.h

在项目里面引入了patron，无奈使用

gem install patron -v 0.4.18 安装的时候一直报错，提示信息如下

e:\ATT\Devkit>
e:\ATT\Devkit>gem install patron -v 0.4.18
Temporarily enhancing PATH to include DevKit...
Building native extensions.  This could take a while...
ERROR:  Error installing patron:
ERROR: Failed to build gem native extension.

E:/ATT/ATT_rake_server_ruby187/ruby/bin/ruby.exe extconf.rb
checking for curl-config... no
checking for main() in -lcurl... 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=.
--srcdir=.
--curdir
--ruby=E:/ATT/ATT_rake_server_ruby187/ruby/bin/ruby
--with-curl-dir
--without-curl-dir
--with-curl-include
--without-curl-include=${curl-dir}/include
--with-curl-lib
--without-curl-lib=${curl-dir}/lib
--with-curllib
--without-curllib
extconf.rb:34:   Can't find libcurl or curl/curl.h (RuntimeError)

Try passing --with-curl-dir or --with-curl-lib and --with-curl-include
options to extconf.

Gem files will remain installed in E:/ATT/ATT_rake_server_ruby187/ruby/lib/ruby/
gems/1.8/gems/patron-0.4.18 for inspection.
Results logged to E:/ATT/ATT_rake_server_ruby187/ruby/lib/ruby/gems/1.8/gems/pat
ron-0.4.18/ext/patron/gem_make.out

异常原因：

没有将curl库编译进去，导致无法安装

解决方法：

在gem 后面加上如下格式参数

gem install --local patron-0.4.18.gem<strong><span style="color:#ff0000;"> -- --with-curl-lib="..\curl\bin" --with-curl-include="..\curl\include"</span></strong>
Temporarily enhancing PATH to include DevKit...
Building native extensions.  This could take a while...
Successfully installed patron-0.4.18
1 gem installed