Ruby on rails 在OS X 10.9上安装kdtree时，未能编译本机扩展

在您的机器上编译kdtree gem的本机扩展时可能会遇到问题。错误可能看起来有点像以下内容：

X-MacBook-Pro:Pitot X$ sudo gem install kdtree
Building native extensions.  This could take a while...
ERROR:  Error installing kdtree:
ERROR: Failed to build gem native extension.

/Users/X/.rvm/rubies/ruby-1.9.3-p327/bin/ruby extconf.rb
creating Makefile

make
compiling kdtree.c
In file included from /Users/X/.rvm/rubies/ruby-1.9.3-p327/include/ruby-1.9.1/ruby.h:32,
             from kdtree.c:1:
/Users/X/.rvm/rubies/ruby-1.9.3-p327/include/ruby-1.9.1/ruby/ruby.h:48:21: error: string.h: No such file or directory
/Users/X/.rvm/rubies/ruby-1.9.3-p327/include/ruby-1.9.1/ruby/ruby.h:58:21: error: stdint.h: No such file or directory
/Users/X/.rvm/rubies/ruby-1.9.3-p327/include/ruby-1.9.1/ruby/ruby.h:61:23: error: inttypes.h: No such file or directory
/Users/X/.rvm/rubies/ruby-1.9.3-p327/include/ruby-1.9.1/ruby/ruby.h:65:19: error: stdio.h: No such file or directory

<snip>

X-MacBook-Pro:Pitot X$sudo gem安装kdtree
构建本机扩展。这可能需要一段时间。。。
错误：安装kdtree时出错：
错误：无法生成gem本机扩展。
/Users/X/.rvm/rubies/ruby-1.9.3-p327/bin/ruby extconf.rb
创建Makefile
制作
编译kdtree.c
在/Users/X/.rvm/rubies/ruby-1.9.3-p327/include/ruby-1.9.1/ruby.h:32中包含的文件中，
从kdtree.c:1：
/Users/X/.rvm/rubies/ruby-1.9.3-p327/include/ruby-1.9.1/ruby/ruby.h:48:21:错误：string.h:没有这样的文件或目录
/Users/X/.rvm/rubies/ruby-1.9.3-p327/include/ruby-1.9.1/ruby/ruby.h:58:21:错误：stdint.h:没有这样的文件或目录
/Users/X/.rvm/rubies/ruby-1.9.3-p327/include/ruby-1.9.1/ruby/ruby.h:61:23:错误：inttypes.h:没有这样的文件或目录
/Users/X/.rvm/rubies/ruby-1.9.3-p327/include/ruby-1.9.1/ruby/ruby.h:65:19:错误：stdio.h:没有这样的文件或目录

这可以通过运行以下命令来解决：

xcode-select --install

然后运行：

sudo gem install kdtree

---

在运行捆绑机之前。

这可以通过运行以下命令来解决：

xcode-select --install

然后运行：

sudo gem install kdtree

在运行捆绑机之前