rbconfig.rb. (backported from CVS HEAD)

* ext/socket/extconf.rb (sockaddr_storage): winsock2.h have the
  definition of struct sockaddr_storage, but socket.c doesn't
  include it because this version of ruby still has binary level
  compatibility with winsock1.

* lib/mkmf.rb (create_makefile): should support header files in
  depend file.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@7907 b2dd03c8-39d4-4d8f-98ff-823fe69b080e