[root@localhost php-5.2.17]# gem install rails -v 3.2.13


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

/usr/bin/ruby extconf.rb
mkmf.rb can't find header files for ruby at /usr/lib/ruby/ruby.h


Gem files will remain installed in /usr/lib/ruby/gems/1.8/gems/json-1.8.3 for inspection.
Results logged to /usr/lib/ruby/gems/1.8/gems/json-1.8.3/ext/json/ext/generator/gem_make.out