Instale o Ruby Gem God no SCL Ruby193

Question

Instalei o Ruby 1.9.3 no Centos 7:

ruby 1.9.3p484 (2013-11-22) [x86_64-linux]

Estou tentando instalar a gema "deus".

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

        /opt/rh/ruby193/root/usr/bin/ruby extconf.rb
mkmf.rb can't find header files for ruby at /opt/rh/ruby193/root/usr/share/include/ruby.h


Gem files will remain installed in /opt/rh/ruby193/root/usr/local/share/gems/gems/god-0.13.7 for inspection.
Results logged to /opt/rh/ruby193/root/usr/local/share/gems/gems/god-0.13.7/ext/god/gem_make.out

O conteúdo de gem_make.out nada mais é do que o erro acima. Eu instalei ruby193-ruby-libs e ruby193-build, mas ainda estou recebendo o mesmo erro. Como posso construir deus com o SCL Ruby 1.9.3?