How to compile Ruby-GNOME2 with several ruby binaries

Sometimes you want to compile libraries under several ruby version.

You can compile Ruby-GNOME2 in separate directories.

% mkdir build-ruby18
% cd build-ruby18
% ruby (Ruby-GNOME2 directory)/extconf.rb
% make 
% cd ..
% mkdir build-ruby19
% cd build-ruby19
% ruby19 (Ruby-GNOME2 directory)/extconf.rb
% make 
% cd ..
% mkdir build-yarv
% cd build-yarv
% ruby-yarv (Ruby-GNOME2 directory)/extconf.rb
% make