rbinstall.rb: install iff expected platforms [ci skip]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56069 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
rbinstall.rb: install iff expected platforms [ci skip]
platforms. e.g., ignore json-java.gemspec in json gem.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56069 b2dd03c8-39d4-4d8f-98ff-823fe69b080e