socket/option.c: fix inet_ntop link error on mswin

* ext/socket/option.c (inet_ntop): link aliased inet_ntop in
  libruby on mswin not rb_w32_inet_ntop which fails to link for
  unknown reason.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48714 b2dd03c8-39d4-4d8f-98ff-823fe69b080e