Installing ruby debug19. Compiler failed to generate an executable file - ruby-on-rails

Question

I am trying to install ruby debug 19 so I can run spork. I am getting errors though that are very frustrating. I've googled for a while to no avail. I am running 1.9.3-p194.
Here's the error message:
Building native extensions. This could take a while...
ERROR: Error installing ruby-debug19:
ERROR: Failed to build gem native extension.
/Users/jasonvdm/.rvm/rubies/ruby-1.9.3-p194/bin/ruby extconf.rb
checking for rb_method_entry_t.body in method.h... *** 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
--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=.
--curdir
--ruby=/Users/jasonvdm/.rvm/rubies/ruby-1.9.3-p194/bin/ruby
--with-ruby-dir
--without-ruby-dir
--with-ruby-include
--without-ruby-include=${ruby-dir}/include
--with-ruby-lib
--without-ruby-lib=${ruby-dir}/lib
/Users/jasonvdm/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:381:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
from /Users/jasonvdm/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:491:in `block in try_compile'
from /Users/jasonvdm/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:443:in `with_werror'
from /Users/jasonvdm/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:491:in `try_compile'
from /Users/jasonvdm/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:1002:in `block in have_struct_member'
from /Users/jasonvdm/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:790:in `block in checking_for'
from /Users/jasonvdm/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:284:in `block (2 levels) in postpone'
from /Users/jasonvdm/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:254:in `open'
from /Users/jasonvdm/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:284:in `block in postpone'
from /Users/jasonvdm/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:254:in `open'
from /Users/jasonvdm/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:280:in `postpone'
from /Users/jasonvdm/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:789:in `checking_for'
from /Users/jasonvdm/.rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/mkmf.rb:1001:in `have_struct_member'
from extconf.rb:10:in `block in <main>'
from /Users/jasonvdm/.rvm/gems/ruby-1.9.3-p194#wheelz/gems/ruby_core_source-0.1.5/lib/ruby_core_source.rb:18:in `call'
from /Users/jasonvdm/.rvm/gems/ruby-1.9.3-p194#wheelz/gems/ruby_core_source-0.1.5/lib/ruby_core_source.rb:18:in `create_makefile_with_core'
from extconf.rb:24:in `<main>'

Answer 1

I had a similar problem, but with installing the nokogiri gem, and I solved it with the following:
cd /usr/bin
sudo ln -s llvm-gcc-4.2 gcc-4.2
See Bundle update & install fail after OS X lion upgrade - Rails 3

Answer 2

Use the debugger gem instead. ruby-debug19 never grew up to support ruby1.9.3