Gem::Installer::ExtensionBuildError: ERROR: Failed to build gem native extension.

/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/bin/ruby extconf.rb
*** 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
extconf.rb:13: uninitialized constant Gem (NameError)
Checking for Python...

Gem files will remain installed in /Users/tmcw/.bundler/tmp/25498/gems/libv8-3.3.10.4 for inspection.
Results logged to /Users/tmcw/.bundler/tmp/25498/gems/libv8-3.3.10.4/ext/libv8/gem_make.out
An error occurred while installing libv8 (3.3.10.4), and Bundler cannot continue.
Make sure that `gem install libv8 -v '3.3.10.4'` succeeds before bundling.