raise if there is no pkg_config for proper libvips versions available
raise if there is no pkg_config for proper libvips versions available

househappy/ruby-vips,jcupitt/ruby-vips,mariovisic/ruby-vips,jcupitt/ruby-vips,househappy/ruby-vips,househappy/ruby-vips,cloudinary/ruby-vips,househappy/ruby-vips,mariovisic/ruby-vips,cloudinary/ruby-vips