hash.c: replace undef
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46540 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
hash.c: replace undef
undefined conversions.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46540 b2dd03c8-39d4-4d8f-98ff-823fe69b080e