struct.c: rb_struct_define_under
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42348 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
struct.c: rb_struct_define_under
under the given namespace, not under Struct. [Feature #8264]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42348 b2dd03c8-39d4-4d8f-98ff-823fe69b080e