error when installing posix-spawn gem with JRuby 1.6.7

error

Installing posix-spawn (0.3.6) with native extensions 
Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

        /Users/Owen/.rvm/rubies/jruby-1.6.7/bin/jruby extconf.rb 
WARNING: JRuby does not support native extensions or the `mkmf' library very well.
Check http://kenai.com/projects/jruby/pages/Home for alternatives.
creating Makefile

make
cc -I. -I/Users/Owen/.rvm/rubies/jruby-1.6.7/lib/native/include -I/Users/Owen/.rvm/rubies/jruby-1.6.7/lib/native/include/ruby -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE      -fPIC -DTARGET_RT_MAC_CFM=0  -fno-omit-frame-pointer -fno-strict-aliasing  -fexceptions   -Wall   -arch i386 -c posix-spawn.c
cc -dynamic -bundle -undefined dynamic_lookup  -o posix_spawn_ext.bundle posix-spawn.o -L"." -L"/Users/Owen/.rvm/rubies/jruby-1.6.7/lib" -bundle -framework JavaVM -Wl,-syslibroot, -mmacosx-version-min=10.5   -arch i386  
ld: library not found for -lbundle1.o
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [posix_spawn_ext.bundle] Error 1


Gem files will remain installed in /Users/Owen/.rvm/gems/jruby-1.6.7/gems/posix-spawn-0.3.6 for inspection.
Results logged to /Users/Owen/.rvm/gems/jruby-1.6.7/gems/posix-spawn-0.3.6/ext/gem_make.out
An error occured while installing posix-spawn (0.3.6), and Bundler cannot continue.
Make sure that `gem install posix-spawn -v '0.3.6'` succeeds before bundling.

my results

qmx@gondor ~ » rvm install jruby-1.6.7
jruby-1.6.7 - #fetching 
jruby-1.6.7 - #downloading jruby-bin-1.6.7, this may take a while depending on your connection...
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 14.8M  100 14.8M    0     0  95002      0  0:02:43  0:02:43 --:--:-- 94344
jruby-1.6.7 - #extracting jruby-bin-1.6.7 to /Users/qmx/.rvm/src/jruby-1.6.7
jruby-1.6.7 - #extracted to /Users/qmx/.rvm/src/jruby-1.6.7
Building Nailgun
jruby-1.6.7 - #installing to /Users/qmx/.rvm/rubies/jruby-1.6.7
jruby-1.6.7 - #importing default gemsets (/Users/qmx/.rvm/gemsets/)
Copying across included gems
Fetching: jruby-launcher-1.0.12-java.gem (100%)
Building native extensions.  This could take a while...
Successfully installed jruby-launcher-1.0.12-java
1 gem installed
qmx@gondor ~ » rvm use jruby-1.6.7
Using /Users/qmx/.rvm/gems/jruby-1.6.7
qmx@gondor ~ » gem install posix-spawn
Fetching: posix-spawn-0.3.6.gem (100%)
Building native extensions.  This could take a while...
Successfully installed posix-spawn-0.3.6
1 gem installed
qmx@gondor ~ »