Ruby

[ruby/stringio] Various cleanup for JRuby ext
(https://github.com/ruby/stringio/pull/85)

• Fix compile warnings on latest Java.
• Adjust one test for JRuby erroring on bad pos= value.
• Replace hard JVM synchronization with a spin lock.
• Avoid duplicate reads of state fields where possible.
• Remove long-deprecated codepoints, chars, bytes, lines methods.
• Mark fcntl as not implemented
• Split most of the remaining variable-arity methods.

https://github.com/ruby/stringio/commit/31a9d42e6c