merge revision(s) 55613: [Backport #12575]
* thread.c (rb_wait_for_single_fd): Clean up fds.revents every time before calling ppoll(2). [Bug #12575] [ruby-dev:49725]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@55957 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merge revision(s) 55613: [Backport #12575]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_3@55957 b2dd03c8-39d4-4d8f-98ff-823fe69b080e