* io.c (rb_update_max_fd): fstat(2) can fail with other than
EBADF. [ruby-dev:44837] [Backport #4339]. Cf.
http://pubs.opengroup.org/onlinepubs/9699919799/functions/fstat.html
EBADF. [ruby-dev:44837] [Bug #5593]. Cf.
merge revision(s) 33691,33692:
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_9_3@34445 b2dd03c8-39d4-4d8f-98ff-823fe69b080e