Ruby pty extension license
['https://github.com/ruby/ruby/blob/9f6deaa6888a423720b4b127b5314f0ad26cc2e6/ext/pty/pty.c#L775-L786', 'https://github.com/ruby/ruby/commit/0a64817fb80016030c03518fb9459f63c11605ea#diff-ef5fa30838d6d0cecad9e675cc50b24628cfe2cb277c346053fafcc36c91c204', 'https://github.com/ruby/ruby/commit/0a64817fb80016030c03518fb9459f63c11605ea#diff-fedf217c1ce44bda01f0a678d3ff8b198bed478754d699c527a698ad933979a0']