add autoload :TransactionState to fix Marshal.load issues
revised changelog comment to be less than 80 chars
Added platform dependent gems


See #12475

If people are on rbx they will get the desired gem
Warning removed for ruby-head
Merge pull request #12800 from raysrashmi/warning-removed-ruby-trunk

Warning removed for ruby-head
Merge pull request #12795 from arunagw/plateform-dependent-gems

Added platform dependent gems
Merge pull request #12791 from jasonayre/ja/fix_autoload_error

add autoload :TransactionState to fix Marshal.load issues