gem install bluecloth -v '2.2.0' --platform=ruby
Building native extensions.  This could take a while...
ERROR:  Error installing bluecloth:
	ERROR: Failed to build gem native extension.

        /Users/davidvolz/.rvm/rubies/ruby-1.8.7-head/bin/ruby extconf.rb
checking for srand()... no
checking for srandom()... no
checking for random()... no
checking for rand()... no
checking for bzero() in string.h,strings.h... no
checking for strcasecmp()... no
checking for stricmp()... no
This extension requires either strcasecmp() or stricmp()
*** 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=/Users/davidvolz/.rvm/rubies/ruby-1.8.7-head/bin/ruby


Gem files will remain installed in /Users/davidvolz/.rvm/gems/ruby-1.8.7-head/gems/bluecloth-2.2.0 for inspection.
Results logged to /Users/davidvolz/.rvm/gems/ruby-1.8.7-head/gems/bluecloth-2.2.0/ext/gem_make.out