Ruby script server/console through readline (LoadError)

i have centos5.1 and ruby version “ruby 1.8.6 (2007-03-13 patchlevel 0)
[x86_64-linux]” “gem version 1.3.5”

[root@localhost]$ script/console
./script/…/config/boot.rb:25:Warning: Gem::SourceIndex#search support
for String patterns is deprecated, use #find_name
Loading development environment.
/usr/local/lib/ruby/1.8/irb/completion.rb:10:in require': no such file to load -- readline (LoadError) from /usr/local/lib/ruby/1.8/irb/completion.rb:10 from /usr/local/lib/ruby/1.8/irb/init.rb:252:inrequire’
from /usr/local/lib/ruby/1.8/irb/init.rb:252:in load_modules' from /usr/local/lib/ruby/1.8/irb/init.rb:250:ineach’
from /usr/local/lib/ruby/1.8/irb/init.rb:250:in load_modules' from /usr/local/lib/ruby/1.8/irb/init.rb:21:insetup’
from /usr/local/lib/ruby/1.8/irb.rb:54:in `start’
from /usr/local/bin/irb:13

and then i have installed the following for fix that error

$> yum install readline-devel -y
$> cd /root/src/ruby-1.8.6/ext/readline/
$> ruby extconf.rb
$> make

the make through the following message;;

make: Nothing to be done for `all’.