Gems can't create makefile? Ubuntu 12.04.2

I'm getting the following result when I try to install the passenger & mysql gems.

I've followed the Ubuntu Hardy articles to setup my slice, apache & ruby/rails.

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sudo gem install mysql
Bulk updating Gem source index for: http://gems.rubyforge.org/
.............
complete
Building native extensions. This could take a while...
ERROR: Error installing mysql:
ERROR: Failed to build gem native extension.

/usr/bin/ruby1.8 extconf.rb install mysql
checking for mysql_query() in -lmysqlclient... yes
checking for mysql_ssl_set()... yes
checking for mysql.h... no
checking for mysql/mysql.h... yes
creating Makefile

make
sh: make: not found

Gem files will remain installed in /usr/lib/ruby/gems/1.8/gems/mysql-2.7 for inspection.
Results logged to /usr/lib/ruby/gems/1.8/gems/mysql-2.7/gem_make.out

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Ok so this problem was happening with several gems. After some hunting I realised make wasn't installed.

I assume I missed a line out somewhere, the following command solved it;
sudo apt-get install build-essential

Thanks to anima from http://forum.slicehost.com