У всех, у кого есть проблемы с установкой gem bson_ext в OSX lion

OSX Lion, Xcode 4.2, GCC 4.2

Я получаю следующая ошибка при установке bson_ext 1.4.1

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

/Users/user/.rvm/rubies/ruby-1.9.2-p290/bin/ruby extconf.rb
checking for asprintf()... *** 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.