bundle install error

output.txt

Gem::Ext::BuildError: ERROR: Failed to build gem native extension.

    /Users/atz/.rvm/rubies/ruby-1.9.3-p547/bin/ruby extconf.rb 
checking for main() in -lstdc++... yes
creating Makefile

make  clean

make
compiling unf.cc
In file included from unf.cc:1:
In file included from ./unf/normalizer.hh:4:
In file included from /Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/vector:265:
In file included from /Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/__bit_reference:15:
In file included from /Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/algorithm:628:
In file included from /Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/memory:604:
/Library/Developer/CommandLineTools/usr/bin/../include/c++/v1/iterator:341:10: fatal error: '__debug' file not found
#include <__debug>
         ^
1 error generated.
make: *** [unf.o] Error 1

make failed, exit code 2

Gem files will remain installed in /Users/atz/.rvm/gems/ruby-1.9.3-p547/gems/unf_ext-0.0.7.1 for inspection.
Results logged to /Users/atz/.rvm/gems/ruby-1.9.3-p547/extensions/x86_64-darwin-13/1.9.1/unf_ext-0.0.7.1/gem_make.out
An error occurred while installing unf_ext (0.0.7.1), and Bundler cannot continue.
Make sure that `gem install unf_ext -v '0.0.7.1'` succeeds before bundling.

Or, just open XCode and accept the license agreement, if it pops up.

Hey - I'm not OP, but you guys are life savers. Updating xcode worked!