Installing theRubyRacer on OSX Lion w/Xcode 4.2.1

gem install therubyracer

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

/Users/marlon/.rvm/rubies/ruby-1.9.2-p290/bin/ruby extconf.rb
checking for main() in -lobjc... *** 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
  --without-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/marlon/.rvm/rubies/ruby-1.9.2-p290/bin/ruby
  --with-objclib
  --without-objclib
/Users/marlon/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/mkmf.rb:368:in `try_do': The complier failed to generate an executable file. (RuntimeError)
You have to install development tools first.
  from /Users/marlon/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/mkmf.rb:435:in `try_link0'
  from /Users/marlon/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/mkmf.rb:440:in `try_link'
  from /Users/marlon/.rvm/rubies/ruby-1.9.2-p290/lib/ruby/1.9.1/mkmf.rb:552:in `try_func'

"/usr/bin/gcc-4.2 -o conftest -I/Users/marlon/.rvm/rubies/ruby-1.9.2-p290/include/ruby-1.9.1/x86_64-darwin11.0.0 -I/Users/marlon/.rvm/rubies/ruby-1.9.2-p290/include/ruby-1.9.1/ruby/backward -I/Users/marlon/.rvm/rubies/ruby-1.9.2-p290/include/ruby-1.9.1 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE    -O3 -ggdb -Wextra -Wno-unused-parameter -Wno-parentheses -Wpointer-arith -Wwrite-strings -Wno-missing-field-initializers -Wshorten-64-to-32 -Wno-long-long  -fno-common -pipe conftest.c  -L. -L/Users/marlon/.rvm/rubies/ruby-1.9.2-p290/lib -L. -L/usr/local/lib     -lruby.1.9.1-static  -lpthread -ldl -lobjc "
checked program was:
/* begin */
1: #include "ruby.h"
2: 
3: int main() {return 0;}
/* end */