how to get ruby 1.9.3-p125 and ruby-debug working on ubuntu 11.10

Gemfile

source 'http://rubygems.org'

# your gems here.

group :development do
  # from http://beginrescueend.com/support/troubleshooting/
  # requires running:  
  #   $ rvm reinstall 1.9.3 --patch debug --force-autoconf
  #
  # my platform section below may be debatable (lots of ways to skin the cat) but the crucial part 
  # is passing the --with-ruby-include param set to your rubies/src dir, where the 
  # debug patch was rebuilt, otherwise it won't work.  AFAIK, there is no way to pass this
  # param with the bundler gem dsl, most current instructions say to run it from cli, but 
  # that forces you to manually update your gemsets, which I didn't like... so you get this
  # (note: Gem.avaliable?(name) is deprecated, hence the find_by_name awkwardness)
  platform :ruby_19 do
    def available?(gem_name)
      begin
        (Gem::Specification::find_by_name(gem_name).nil?) ? false : true
      rescue Exception => e
        false
      end
    end

    unless available?('ruby-debug19') || (RUBY_VERSION != "1.9.3")
      system('gem install ruby-debug19 -- --with-ruby-include=$rvm_path/src')
    else
      gem 'ruby-debug19'
    end
  end
end

steps.log

# 1) run:
$ rvm reinstall 1.9.3 --patch debug --force-autoconf
Removing /local/rvm/src/ruby-1.9.3-p125...
Removing /local/rvm/rubies/ruby-1.9.3-p125...
Removing ruby-1.9.3-p125 aliases...
Removing ruby-1.9.3-p125 wrappers...
Removing ruby-1.9.3-p125 environments...
Removing ruby-1.9.3-p125 binaries...
Installing Ruby from source to: /local/rvm/rubies/ruby-1.9.3-p125, this may take a while depending on your cpu(s)...

ruby-1.9.3-p125 - #fetching 
ruby-1.9.3-p125 - #extracted to /local/rvm/src/ruby-1.9.3-p125 (already extracted)
Applying patch 'debug' (located at /local/rvm/patches/ruby/1.9.3/p125/debug.diff)
Error running 'patch -F 25 -p1 -N -f <"/local/rvm/patches/ruby/1.9.3/p125/debug.diff"', please read /local/rvm/log/ruby-1.9.3-p125/patch.apply.debug.log
Applying patch 'xcode-debugopt-fix-r34840' (located at /local/rvm/patches/ruby/1.9.3/p125/xcode-debugopt-fix-r34840.diff)
Error running 'patch -F 25 -p1 -N -f <"/local/rvm/patches/ruby/1.9.3/p125/xcode-debugopt-fix-r34840.diff"', please read /local/rvm/log/ruby-1.9.3-p125/patch.apply.xcode-debugopt-fix-r34840.log
ruby-1.9.3-p125 - #autoreconf -f
ruby-1.9.3-p125 - #configuring 
ruby-1.9.3-p125 - #compiling 
ruby-1.9.3-p125 - #installing 
Removing old Rubygems files...
Installing rubygems-1.8.21 for ruby-1.9.3-p125 ...
Installation of rubygems completed successfully.
ruby-1.9.3-p125 - adjusting #shebangs for (gem irb erb ri rdoc testrb rake).
ruby-1.9.3-p125 - #importing default gemsets (/local/rvm/gemsets/)
Install of ruby-1.9.3-p125 - #complete 

# 2) ignore the errors above, it still worked ok as long as it gets to 'complete'

# 3) adapt the Gemfile above for your own projects. It will work for any ruby 1.9.

# 4) run:
$ rvm reload
RVM reloaded!
$ rvm gemset empty
Are you SURE you wish to remove the installed gems for gemset 'ruby-1.9.3-p125@myset' (/local/rvm/gems/ruby-1.9.3-p125@myset)?
(anything other than 'yes' will cancel) > yes
$ bundle install

# 5) use ruby-debug e.g.:
require 'ruby-debug'
def some_method
  debugger
end

# 6) $ ruby my_codz.rb
[84, 87] in /tmp/my_codz.rb
   84      def some_method
   85        debugger
=> 86        print '.'
   87      end
/tmp/my_codz.rb:87
print '.'
(rdb:1)

# yays!