rugged error

gistfile1.txt

sudo gem install rugged
Password:
Building native extensions.  This could take a while...
ERROR:  Error installing rugged:
	ERROR: Failed to build gem native extension.

        /System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby extconf.rb
 -- tar zxvf libgit2-dist.tar.gz
 -- make -f Makefile.embed
checking for main() in -lgit2_embed... no
ERROR: Failed to build libgit2
*** 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=/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby
	--with-git2_embedlib
	--without-git2_embedlib


Gem files will remain installed in /Library/Ruby/Gems/1.8/gems/rugged-0.16.0 for inspection.
Results logged to /Library/Ruby/Gems/1.8/gems/rugged-0.16.0/ext/rugged/gem_make.out