gollum error

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

    /Users/samuelcolon/.rvm/rubies/ruby-2.1.0/bin/ruby extconf.rb
checking for main() in -licui18n... no
checking for main() in -licui18n... no


***************************************************************************************
*********** icu required (brew install icu4c or apt-get install libicu-dev) ***********
***************************************************************************************
*** 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/samuelcolon/.rvm/rubies/ruby-2.1.0/bin/ruby
	--with-icu-dir
	--without-icu-dir
	--with-icu-include
	--without-icu-include=${icu-dir}/include
	--with-icu-lib
	--without-icu-lib=${icu-dir}/lib
	--with-icui18nlib
	--without-icui18nlib
	--with-icui18nlib
	--without-icui18nlib

extconf failed, exit code 1

Gem files will remain installed in /Users/samuelcolon/.rvm/gems/ruby-2.1.0/gems/charlock_holmes-0.6.9.4 for inspection.
Results logged to /Users/samuelcolon/.rvm/gems/ruby-2.1.0/extensions/x86_64-darwin-12/2.1.0-static/charlock_holmes-0.6.9.4/gem_make.out
samuelcolonsmbp:depot samuelcolon$