dir.c: use packed structs
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49712 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
dir.c: use packed structs
packed structs instead of arrays to suppress warning by older
versions of gcc.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@49712 b2dd03c8-39d4-4d8f-98ff-823fe69b080e